{"product_id":"forensics-detectors-4-gas-monitor-usb-rechargeable","title":"Forensics Detectors 4 Gas Monitor (USB Rechargeable, NIST Calibrated)","description":"\u003c!-- PRODUCT B07J1WQST5 | tag portable-gas-detector | TODO: add matching Product Review + best-of guide links when those silo layers exist --\u003e\n\n\u003cdiv style=\"background:#1a1a1a;border-left:4px solid #ff9800;padding:14px 18px;margin:0 0 18px 0;color:#f5e6d3;font-size:0.95em;\"\u003e\n\u003cstrong style=\"color:#ffb74d;\"\u003eEditor’s note:\u003c\/strong\u003e the Forensics Detectors 4 gas monitor is one of the portable instruments we curate in our \u003ca href=\"\/collections\/portable-gas-detectors\" title=\"Portable Gas Detectors\"\u003ePortable Gas Detectors\u003c\/a\u003e buyer’s hub. Compare it head-to-head with the \u003ca href=\"\/products\/forensics-detectors-4-gas-meter-confined-space\" title=\"Forensics Detectors 4 Gas Meter\"\u003eForensics Detectors 4 Gas Meter\u003c\/a\u003e below before you order.\u003c\/div\u003e\n\n\u003ch2 id=\"top\"\u003eForensics Detectors 4 Gas Monitor — USB-Rechargeable O2, CO, H2S \u0026amp; LEL\u003c\/h2\u003e\n\n\u003cp\u003eThe \u003cstrong\u003eForensics Detectors 4 gas monitor\u003c\/strong\u003e is the USB-rechargeable member of the Forensics family, reading oxygen (O2), combustible gas (LEL), carbon monoxide (CO) and hydrogen sulfide (H2S) with a NIST certificate and triple alarms. It is the \u003ca href=\"\/collections\/portable-gas-detectors\" title=\"portable gas detector\"\u003eportable gas detector\u003c\/a\u003e to pick when you want simple USB charging and a long, well-reviewed track record.\u003c\/p\u003e\n\n\u003cp style=\"font-size:0.9em;color:#bdae9d;margin:10px 0 18px 0;\"\u003eJump to: \u003ca href=\"#features\" style=\"color:#ffb74d;\"\u003eFeatures\u003c\/a\u003e · \u003ca href=\"#specs\" style=\"color:#ffb74d;\"\u003eSpecs\u003c\/a\u003e · \u003ca href=\"#compatibility\" style=\"color:#ffb74d;\"\u003eWhat it detects\u003c\/a\u003e · \u003ca href=\"#comparison\" style=\"color:#ffb74d;\"\u003eComparison\u003c\/a\u003e · \u003ca href=\"#faq\" style=\"color:#ffb74d;\"\u003eFAQ\u003c\/a\u003e\u003c\/p\u003e\n\n\u003cp\u003eThe Forensics Detectors 4 Gas Monitor is a USB-rechargeable, electrochemical four-gas instrument (O2, CO, H2S, LEL) with a NIST certificate, built for \u003ca href=\"\/collections\/portable-gas-detectors\" title=\"portable\"\u003eportable\u003c\/a\u003e confined-space and field monitoring.\u003c\/p\u003e\n\n\u003ch3 id=\"features\"\u003eKey features\u003c\/h3\u003e\n\n\u003cul\u003e\n\u003cli\u003eMonitors oxygen (O2), combustible gas (LEL), carbon monoxide (CO) and hydrogen sulfide (H2S) on a single backlit display\u003c\/li\u003e\n\u003cli\u003eUSB-rechargeable — top it up from a laptop, power bank or wall adapter between shifts\u003c\/li\u003e\n\u003cli\u003eIncludes a USA NIST calibration certificate for documented accuracy\u003c\/li\u003e\n\u003cli\u003eAudible, vibration and visual alarms for multi-environment alerting\u003c\/li\u003e\n\u003cli\u003eElectrochemical sensors with zero\/span calibration for field accuracy\u003c\/li\u003e\n\u003cli\u003eMost-reviewed Forensics four-gas unit we stock (123 ratings)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cdiv style=\"display:flex;gap:14px;flex-wrap:wrap;margin:18px 0;\"\u003e\n\u003cdiv style=\"flex:1;min-width:240px;background:#1b3a2a;border:1px solid #4caf50;border-radius:6px;padding:14px 18px;\"\u003e\n\u003cstrong style=\"color:#81c784;\"\u003ePros\u003c\/strong\u003e\u003cul style=\"margin:8px 0 0 0;\"\u003e\n\u003cli\u003eUSB-rechargeable convenience\u003c\/li\u003e\n\u003cli\u003eNIST calibration certificate included\u003c\/li\u003e\n\u003cli\u003eStrong, well-reviewed track record (123 ratings)\u003c\/li\u003e\n\u003cli\u003eTriple alarm modes\u003c\/li\u003e\n\u003cli\u003ePocketable confined-space form factor\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv style=\"flex:1;min-width:240px;background:#3a1e1e;border:1px solid #ef5350;border-radius:6px;padding:14px 18px;\"\u003e\n\u003cstrong style=\"color:#e57373;\"\u003eCons\u003c\/strong\u003e\u003cul style=\"margin:8px 0 0 0;\"\u003e\n\u003cli\u003eDiffusion sampling only — no pump for remote sampling\u003c\/li\u003e\n\u003cli\u003eHeavier (9.6 oz) than the lightweight 4 Gas Meter\u003c\/li\u003e\n\u003cli\u003eElectrochemical sensors need periodic replacement\u003c\/li\u003e\n\u003cli\u003eField-grade; not a docking-station fleet instrument\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\n\u003ch3 id=\"specs\"\u003eSpecifications\u003c\/h3\u003e\n\n\u003cdiv style=\"overflow-x:auto;\"\u003e\u003ctable style=\"width:100%;border-collapse:collapse;background:#1a1a1a;margin:14px 0;\"\u003e\n\u003cthead\u003e\u003ctr style=\"background:#2a2a2a;\"\u003e\n\u003cth style=\"color:#ffb74d;padding:8px 10px;border:1px solid #3a3a3a;text-align:left;\"\u003eSpecification\u003c\/th\u003e\n\u003cth style=\"color:#ffb74d;padding:8px 10px;border:1px solid #3a3a3a;text-align:left;\"\u003eDetail\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd style=\"color:#ffb74d;padding:8px 10px;border:1px solid #3a3a3a;white-space:nowrap;\"\u003eGases detected\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:8px 10px;border:1px solid #3a3a3a;\"\u003eO2, CO, H2S, LEL combustibles\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"color:#ffb74d;padding:8px 10px;border:1px solid #3a3a3a;white-space:nowrap;\"\u003eSensor type\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:8px 10px;border:1px solid #3a3a3a;\"\u003eElectrochemical\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"color:#ffb74d;padding:8px 10px;border:1px solid #3a3a3a;white-space:nowrap;\"\u003eAlarms\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:8px 10px;border:1px solid #3a3a3a;\"\u003eAudible, vibration \u0026amp; visual\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"color:#ffb74d;padding:8px 10px;border:1px solid #3a3a3a;white-space:nowrap;\"\u003eCalibration\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:8px 10px;border:1px solid #3a3a3a;\"\u003eZero \u0026amp; span; NIST certificate included\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"color:#ffb74d;padding:8px 10px;border:1px solid #3a3a3a;white-space:nowrap;\"\u003ePower\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:8px 10px;border:1px solid #3a3a3a;\"\u003eUSB-rechargeable battery\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"color:#ffb74d;padding:8px 10px;border:1px solid #3a3a3a;white-space:nowrap;\"\u003eWeight\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:8px 10px;border:1px solid #3a3a3a;\"\u003e9.6 oz\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"color:#ffb74d;padding:8px 10px;border:1px solid #3a3a3a;white-space:nowrap;\"\u003eDimensions\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:8px 10px;border:1px solid #3a3a3a;\"\u003e1.18\" x 2.64\" x 5.12\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"color:#ffb74d;padding:8px 10px;border:1px solid #3a3a3a;white-space:nowrap;\"\u003eColor\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:8px 10px;border:1px solid #3a3a3a;\"\u003eBlack \/ yellow\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003c\/div\u003e\n\n\u003ch3\u003eWhere the Forensics Detectors USB 4 Gas Monitor fits\u003c\/h3\u003e\n\n\u003cul\u003e\n\u003cli\u003eConfined-space pre-entry checks\u003c\/li\u003e\n\u003cli\u003eUtility, sewer and water-treatment work\u003c\/li\u003e\n\u003cli\u003eOil-and-gas field spot monitoring\u003c\/li\u003e\n\u003cli\u003eFacilities and maintenance rounds\u003c\/li\u003e\n\u003cli\u003eFire-overhaul and rescue support checks\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2 id=\"compatibility\"\u003eWhat the Forensics Detectors USB 4 Gas Monitor detects (and what it doesn’t)\u003c\/h2\u003e\n\n\u003cp\u003eIt measures oxygen (O2), combustible gas (LEL), carbon monoxide (CO) and hydrogen sulfide (H2S) and ships NIST-calibrated. Like most compact four-gas units it uses diffusion sampling, so for remote pre-entry sampling step up to the \u003ca href=\"\/products\/forensics-detectors-4-gas-monitor-with-pump\" title=\"pump version\"\u003epump version\u003c\/a\u003e. It does not detect VOCs, CO2 or single toxic gases such as chlorine — those require a PID or dedicated sensor. Recharge over USB, bump-test daily with four-gas calibration gas, and for all-shift single-worker coverage add a clip from \u003ca href=\"\/collections\/personal-gas-detectors\" title=\"Personal \u0026amp; Wearable Gas Detectors\"\u003ePersonal \u0026amp; Wearable Gas Detectors\u003c\/a\u003e.\u003c\/p\u003e\n\n\u003cp\u003eCross-shopping? This unit sits in our \u003ca href=\"\/collections\/portable-gas-detectors\" title=\"Portable Gas Detectors\"\u003ePortable Gas Detectors\u003c\/a\u003e hub alongside the \u003ca href=\"\/products\/forensics-detectors-4-gas-meter-confined-space\" title=\"Forensics Detectors 4 Gas Meter\"\u003eForensics Detectors 4 Gas Meter\u003c\/a\u003e, \u003ca href=\"\/products\/toptes-guard-863pro-4-gas-monitor\" title=\"TopTes Guard-863Pro\"\u003eTopTes Guard-863Pro\u003c\/a\u003e, \u003ca href=\"\/products\/toptes-guard-101-4-gas-detector\" title=\"TopTes Guard-101\"\u003eTopTes Guard-101\u003c\/a\u003e, \u003ca href=\"\/products\/toptes-guard-156-4-gas-monitor\" title=\"TopTes Guard-156\"\u003eTopTes Guard-156\u003c\/a\u003e. If one worker needs all-shift wear instead of a carried meter, see \u003ca href=\"\/collections\/personal-gas-detectors\" title=\"Personal \u0026amp; Wearable Gas Detectors\"\u003ePersonal \u0026amp; Wearable Gas Detectors\u003c\/a\u003e; for a fixed install or a job-site perimeter, see \u003ca href=\"\/collections\/fixed-gas-detection-systems\" title=\"Fixed Gas Detection Systems\"\u003eFixed Gas Detection Systems\u003c\/a\u003e and \u003ca href=\"\/collections\/area-gas-monitors\" title=\"Area \u0026amp; Transportable Gas Monitors\"\u003eArea \u0026amp; Transportable Gas Monitors\u003c\/a\u003e.\u003c\/p\u003e\n\n\u003ch2 id=\"comparison\"\u003eForensics Detectors 4-gas family compared\u003c\/h2\u003e\n\n\u003cdiv style=\"overflow-x:auto;\"\u003e\u003ctable style=\"width:100%;border-collapse:collapse;background:#1a1a1a;margin:14px 0;\"\u003e\n\u003ccaption style=\"color:#bdae9d;font-size:0.85em;text-align:left;padding:4px 0;\"\u003eForensics Detectors portable 4-gas family (O2, CO, H2S, LEL)\u003c\/caption\u003e\n\u003cthead\u003e\u003ctr style=\"background:#2a2a2a;\"\u003e\n\u003cth style=\"color:#ffb74d;padding:9px;border:1px solid #3a3a3a;text-align:left;\"\u003eModel\u003c\/th\u003e\n\u003cth style=\"color:#ffb74d;padding:9px;border:1px solid #3a3a3a;text-align:left;\"\u003eSampling\u003c\/th\u003e\n\u003cth style=\"color:#ffb74d;padding:9px;border:1px solid #3a3a3a;text-align:left;\"\u003eNIST cert\u003c\/th\u003e\n\u003cth style=\"color:#ffb74d;padding:9px;border:1px solid #3a3a3a;text-align:left;\"\u003eRecharge\u003c\/th\u003e\n\u003cth style=\"color:#ffb74d;padding:9px;border:1px solid #3a3a3a;text-align:left;\"\u003eStreet price\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd style=\"color:#e0e0e0;padding:9px;border:1px solid #3a3a3a;\"\u003e\u003ca href=\"\/products\/forensics-detectors-4-gas-meter-confined-space\" title=\"4 Gas Meter (Confined Space)\"\u003e4 Gas Meter (Confined Space)\u003c\/a\u003e\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:9px;border:1px solid #3a3a3a;\"\u003eDiffusion\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:9px;border:1px solid #3a3a3a;\"\u003eYes\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:9px;border:1px solid #3a3a3a;\"\u003eBattery\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:9px;border:1px solid #3a3a3a;\"\u003e~$199\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"color:#e0e0e0;padding:9px;border:1px solid #3a3a3a;\"\u003e\u003ca href=\"\/products\/forensics-detectors-4-gas-monitor-usb-rechargeable\" title=\"4 Gas Monitor (USB)\"\u003e4 Gas Monitor (USB)\u003c\/a\u003e\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:9px;border:1px solid #3a3a3a;\"\u003eDiffusion\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:9px;border:1px solid #3a3a3a;\"\u003eYes\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:9px;border:1px solid #3a3a3a;\"\u003eUSB rechargeable\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:9px;border:1px solid #3a3a3a;\"\u003e~$225\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background:#2a2520;\"\u003e\n\u003ctd style=\"color:#e0e0e0;padding:9px;border:1px solid #3a3a3a;\"\u003e\u003cstrong\u003e\u003ca href=\"\/products\/forensics-detectors-4-gas-monitor-with-pump\" title=\"4 Gas Monitor + Pump\"\u003e4 Gas Monitor + Pump\u003c\/a\u003e\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:9px;border:1px solid #3a3a3a;\"\u003eMotorized pump + probe\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:9px;border:1px solid #3a3a3a;\"\u003eYes\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:9px;border:1px solid #3a3a3a;\"\u003eUSB rechargeable\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:9px;border:1px solid #3a3a3a;\"\u003e~$299\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003c\/div\u003e\n\n\u003cul\u003e\n\u003cli\u003eChoose this \u003cstrong\u003eUSB 4 Gas Monitor\u003c\/strong\u003e for USB charging and the most-reviewed Forensics option.\u003c\/li\u003e\n\u003cli\u003ePick the lighter \u003ca href=\"\/products\/forensics-detectors-4-gas-meter-confined-space\" title=\"4 Gas Meter\"\u003e4 Gas Meter\u003c\/a\u003e if minimum weight and price matter most.\u003c\/li\u003e\n\u003cli\u003eChoose the \u003ca href=\"\/products\/forensics-detectors-4-gas-monitor-with-pump\" title=\"4 Gas Monitor with Pump\"\u003e4 Gas Monitor with Pump\u003c\/a\u003e when remote sampling is required.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2 id=\"faq\"\u003eFrequently asked questions\u003c\/h2\u003e\n\n\u003ch3\u003eWhat gases does the Forensics Detectors 4 gas monitor detect?\u003c\/h3\u003e\u003cp\u003eIt reads oxygen (O2), combustible gas (LEL), carbon monoxide (CO) and hydrogen sulfide (H2S) — the standard confined-space set. VOCs require a separate PID; see the \u003ca href=\"\/collections\/portable-gas-detectors\" title=\"Portable Gas Detectors\"\u003ePortable Gas Detectors\u003c\/a\u003e hub.\u003c\/p\u003e\n\u003ch3\u003eHow is the Forensics 4 gas monitor recharged?\u003c\/h3\u003e\u003cp\u003eOver USB — from a laptop, power bank or wall adapter. A full charge covers a typical work shift.\u003c\/p\u003e\n\u003ch3\u003eDoes it come NIST calibrated?\u003c\/h3\u003e\u003cp\u003eYes, it ships with a USA NIST calibration certificate. Bump-test before each use and calibrate on schedule to maintain accuracy.\u003c\/p\u003e\n\u003ch3\u003eIs this monitor good for confined-space entry?\u003c\/h3\u003e\u003cp\u003eYes for ongoing monitoring; its O2\/CO\/H2S\/LEL set matches OSHA 1910.146 hazards. For sampling a space before entry, use the \u003ca href=\"\/products\/forensics-detectors-4-gas-monitor-with-pump\" title=\"pump model\"\u003epump model\u003c\/a\u003e.\u003c\/p\u003e\n\u003ch3\u003eHow heavy is it compared to the 4 Gas Meter?\u003c\/h3\u003e\u003cp\u003eAt 9.6 oz it is heavier than the \u003ca href=\"\/products\/forensics-detectors-4-gas-meter-confined-space\" title=\"4.8 oz 4 Gas Meter\"\u003e4.8 oz 4 Gas Meter\u003c\/a\u003e; the trade-off is USB charging and a larger review base.\u003c\/p\u003e\n\u003ch3\u003eWhat alarms does it use?\u003c\/h3\u003e\u003cp\u003eAudible, vibration and visual alarms trigger when a gas crosses its set point, so alerts register in loud or bright conditions.\u003c\/p\u003e\n\u003ch3\u003eHow often should I bump-test and calibrate it?\u003c\/h3\u003e\u003cp\u003eBump-test before each day of use; perform a full zero\/span calibration on the manufacturer's schedule or after any failed bump test.\u003c\/p\u003e\n\u003ch3\u003eHow long do the sensors last?\u003c\/h3\u003e\u003cp\u003eElectrochemical sensors generally last two to three years. Plan for replacement sensors and calibration gas as recurring costs.\u003c\/p\u003e\n\u003ch3\u003eWhat does it not detect?\u003c\/h3\u003e\u003cp\u003eNo VOCs, CO2 or specific toxics like ammonia or chlorine. For VOC work you need a PID; explore options across the \u003ca href=\"\/collections\/portable-gas-detectors\" title=\"Portable Gas Detectors\"\u003ePortable Gas Detectors\u003c\/a\u003e hub.\u003c\/p\u003e\n\u003ch3\u003eCan one monitor cover a whole crew?\u003c\/h3\u003e\u003cp\u003eNo — it monitors the air where it is. For per-worker exposure, issue wearable clips from \u003ca href=\"\/collections\/personal-gas-detectors\" title=\"Personal \u0026amp; Wearable Gas Detectors\"\u003ePersonal \u0026amp; Wearable Gas Detectors\u003c\/a\u003e; for a perimeter use \u003ca href=\"\/collections\/area-gas-monitors\" title=\"Area \u0026amp; Transportable Gas Monitors\"\u003eArea \u0026amp; Transportable Gas Monitors\u003c\/a\u003e.\u003c\/p\u003e\n\u003ch3\u003eIs it in stock?\u003c\/h3\u003e\u003cp\u003eUse the Amazon buy button for live availability and delivery timing through our fulfillment partner.\u003c\/p\u003e\n\u003ch3\u003eIs this a fleet-management instrument?\u003c\/h3\u003e\u003cp\u003eIt is a capable field monitor. Sites needing automated docking-station bump\/cal across large fleets typically specify Industrial Scientific or BW Honeywell.\u003c\/p\u003e\n\n\u003cdiv style=\"background:#1a1a1a;border:1px solid #3a3a3a;border-radius:6px;padding:16px 18px;margin:22px 0;\"\u003e\n\u003cp style=\"margin:0 0 10px 0;color:#f5e6d3;\"\u003eReady to order the \u003cstrong\u003eForensics Detectors 4 gas monitor\u003c\/strong\u003e? Add it to your cart above, or check the current Amazon price below. Compare it against the rest of our \u003ca href=\"\/collections\/portable-gas-detectors\" title=\"Portable Gas Detectors\"\u003ePortable Gas Detectors\u003c\/a\u003e lineup before you buy.\u003c\/p\u003e\n\u003cp style=\"display:flex;gap:10px;flex-wrap:wrap;align-items:center;margin:0;\"\u003e\u003ca href=\"https:\/\/www.amazon.com\/dp\/B07J1WQST5?tag=wcsafety04-20\" rel=\"sponsored nofollow noopener\" target=\"_blank\" style=\"display:inline-block;background:#FFD814;color:#0F1111;padding:13px 26px;text-decoration:none;font-weight:bold;border-radius:4px;border:1px solid #FCD200;\"\u003eCHECK PRICE ON AMAZON →\u003c\/a\u003e\u003cspan style=\"font-size:0.8em;color:#bdae9d;\"\u003eAs an Amazon Associate, WC Safety earns from qualifying purchases.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003cdiv style=\"background:#1a2733;border:1px dashed #4fc3f7;padding:16px 20px;margin:30px 0 18px 0;color:#cfd8dc;font-size:0.92em;\"\u003e\n  \u003cstrong style=\"color:#4fc3f7;\"\u003eWhy trust this Forensics Detectors page?\u003c\/strong\u003e WC Safety is an independent industrial safety-equipment retailer serving safety managers, procurement teams and field supervisors. The specifications on this page are taken from the manufacturer’s published listing for Forensics Detectors USB 4 Gas Monitor and framed against \u003ca href=\"https:\/\/www.osha.gov\/laws-regs\/regulations\/standardnumber\/1910\/1910.146\" rel=\"noopener\" target=\"_blank\" style=\"color:#4fc3f7;\"\u003eOSHA 29 CFR 1910.146\u003c\/a\u003e for confined-space atmospheric testing. Disclosed: WC Safety earns Amazon affiliate commissions on outbound clicks; that does not influence the specs shown or where this unit sits in our lineup.\n\u003c\/div\u003e\n\u003cdiv style=\"background:#1a2733;border-left:4px solid #4fc3f7;padding:18px 22px;margin:18px 0;color:#cfd8dc;font-size:0.92em;\"\u003e\n  \u003cstrong style=\"color:#4fc3f7;\"\u003eBy Steven Eaton, WC Safety Editorial\u003c\/strong\u003e — Industrial safety-equipment desk · specialization: portable atmospheric monitoring, confined-space gas detection and instrument selection.\u003cbr\u003e\n  \u003cstrong\u003eLast updated:\u003c\/strong\u003e \u003ctime datetime=\"2026-06-22\"\u003eJune 22, 2026\u003c\/time\u003e · \u003cstrong\u003eSources reviewed:\u003c\/strong\u003e manufacturer product listing \u0026amp; specifications, OSHA 29 CFR 1910.146, OSHA Annotated PEL tables, ACGIH Threshold Limit Values.\u003cbr\u003e\n  \u003cstrong\u003eEditorial standard:\u003c\/strong\u003e \u003cem\u003eZero sponsored listings. No manufacturer input. Specs verified against the manufacturer’s published data.\u003c\/em\u003e\n\u003c\/div\u003e\n\u003cdiv style=\"background:#1a2733;border-left:4px solid #4fc3f7;padding:16px 20px;margin:18px 0;color:#cfd8dc;font-size:0.92em;\"\u003e\n  \u003cstrong style=\"color:#4fc3f7;\"\u003eHow this page is maintained.\u003c\/strong\u003e Specifications and pricing are reviewed against the manufacturer’s current listing and re-checked whenever the lineup changes. Gas-detection guidance follows \u003ca href=\"https:\/\/www.osha.gov\/laws-regs\/regulations\/standardnumber\/1910\/1910.146\" rel=\"noopener\" target=\"_blank\" style=\"color:#4fc3f7;\"\u003eOSHA 1910.146\u003c\/a\u003e (permit-required confined spaces) and \u003ca href=\"https:\/\/www.osha.gov\/annotated-pels\" rel=\"noopener\" target=\"_blank\" style=\"color:#4fc3f7;\"\u003eOSHA Permissible Exposure Limits\u003c\/a\u003e, cross-referenced with ACGIH TLVs.\n\u003c\/div\u003e\n\u003cdiv style=\"background:#2a2520;border-left:4px solid #ff9800;padding:16px 20px;margin:18px 0;color:#f5e6d3;font-size:0.92em;\"\u003e\n  \u003cstrong style=\"color:#ffb74d;\"\u003eDisclosure.\u003c\/strong\u003e WC Safety participates in the Amazon Associates Program and earns commissions on qualifying purchases through outbound links on this page (tag wcsafety04-20). We are not sponsored by any instrument manufacturer. This page is buyer guidance, not medical, legal or regulatory advice — confirm gas-detection requirements for your site against the applicable OSHA standard and, for commercial monitoring programs, a Certified Industrial Hygienist (CIH).\n\u003c\/div\u003e\n\n\u003cscript type=\"application\/ld+json\"\u003e\n{\"@context\": \"https:\/\/schema.org\", \"@graph\": [{\"@type\": \"Product\", \"@id\": \"https:\/\/wcsafety.com\/products\/forensics-detectors-4-gas-monitor-usb-rechargeable#product\", \"name\": \"Forensics Detectors 4 Gas Monitor (USB Rechargeable, NIST Calibrated)\", \"description\": \"Forensics Detectors 4 gas monitor — USB-rechargeable, NIST-calibrated O2, CO, H2S \u0026 LEL detector with triple alarm. Order at WC Safety.\", \"sku\": \"B07J1WQST5\", \"mpn\": \"FD-90A\", \"image\": [\"https:\/\/wcsafety.com\/cdn\/shop\/products\/forensics-detectors-4-gas-monitor-usb-rechargeable.jpg\"], \"brand\": {\"@type\": \"Brand\", \"name\": \"Forensics Detectors\"}, \"category\": \"Portable Gas Detector\", \"isPartOf\": {\"@type\": \"CollectionPage\", \"@id\": \"https:\/\/wcsafety.com\/collections\/portable-gas-detectors#collection\", \"name\": \"Portable Gas Detectors\", \"url\": \"https:\/\/wcsafety.com\/collections\/portable-gas-detectors\"}, \"isRelatedTo\": [{\"@type\": \"Product\", \"name\": \"Forensics Detectors 4 Gas Meter for Confined Space\", \"url\": \"https:\/\/wcsafety.com\/products\/forensics-detectors-4-gas-meter-confined-space\"}, {\"@type\": \"Product\", \"name\": \"TopTes Guard-863Pro 4 Gas Monitor\", \"url\": \"https:\/\/wcsafety.com\/products\/toptes-guard-863pro-4-gas-monitor\"}, {\"@type\": \"Product\", \"name\": \"TopTes Guard-101 4 Gas Detector\", \"url\": \"https:\/\/wcsafety.com\/products\/toptes-guard-101-4-gas-detector\"}, {\"@type\": \"Product\", \"name\": \"TopTes Guard-156 4 Gas Monitor\", \"url\": \"https:\/\/wcsafety.com\/products\/toptes-guard-156-4-gas-monitor\"}, {\"@type\": \"Product\", \"name\": \"Forensics Detectors 4 Gas Monitor with Pump\", \"url\": \"https:\/\/wcsafety.com\/products\/forensics-detectors-4-gas-monitor-with-pump\"}, {\"@type\": \"Product\", \"name\": \"Forsensal 4 Gas Detector with Pump\", \"url\": \"https:\/\/wcsafety.com\/products\/forsensal-4-gas-detector-with-pump\"}], \"offers\": {\"@type\": \"Offer\", \"url\": \"https:\/\/wcsafety.com\/products\/forensics-detectors-4-gas-monitor-usb-rechargeable\", \"priceCurrency\": \"USD\", \"price\": \"225.45\", \"availability\": \"https:\/\/schema.org\/InStock\", \"seller\": {\"@type\": \"Organization\", \"name\": \"WC Safety\"}}}, {\"@type\": \"BreadcrumbList\", \"@id\": \"https:\/\/wcsafety.com\/products\/forensics-detectors-4-gas-monitor-usb-rechargeable#breadcrumb\", \"itemListElement\": [{\"@type\": \"ListItem\", \"position\": 1, \"name\": \"Home\", \"item\": \"https:\/\/wcsafety.com\/\"}, {\"@type\": \"ListItem\", \"position\": 2, \"name\": \"Gas Detectors\", \"item\": \"https:\/\/wcsafety.com\/collections\/gas-detectors\"}, {\"@type\": \"ListItem\", \"position\": 3, \"name\": \"Portable Gas Detectors\", \"item\": \"https:\/\/wcsafety.com\/collections\/portable-gas-detectors\"}, {\"@type\": \"ListItem\", \"position\": 4, \"name\": \"Forensics Detectors 4 Gas Monitor (USB Rechargeable, NIST Calibrated)\"}]}, {\"@type\": \"FAQPage\", \"mainEntity\": [{\"@type\": \"Question\", \"name\": \"What gases does the Forensics Detectors 4 gas monitor detect?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"It reads oxygen (O2), combustible gas (LEL), carbon monoxide (CO) and hydrogen sulfide (H2S) — the standard confined-space set. VOCs require a separate PID; see the Portable Gas Detectors hub.\"}}, {\"@type\": \"Question\", \"name\": \"How is the Forensics 4 gas monitor recharged?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"Over USB — from a laptop, power bank or wall adapter. A full charge covers a typical work shift.\"}}, {\"@type\": \"Question\", \"name\": \"Does it come NIST calibrated?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"Yes, it ships with a USA NIST calibration certificate. Bump-test before each use and calibrate on schedule to maintain accuracy.\"}}, {\"@type\": \"Question\", \"name\": \"Is this monitor good for confined-space entry?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"Yes for ongoing monitoring; its O2\/CO\/H2S\/LEL set matches OSHA 1910.146 hazards. For sampling a space before entry, use the pump model.\"}}, {\"@type\": \"Question\", \"name\": \"How heavy is it compared to the 4 Gas Meter?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"At 9.6 oz it is heavier than the 4.8 oz 4 Gas Meter; the trade-off is USB charging and a larger review base.\"}}, {\"@type\": \"Question\", \"name\": \"What alarms does it use?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"Audible, vibration and visual alarms trigger when a gas crosses its set point, so alerts register in loud or bright conditions.\"}}, {\"@type\": \"Question\", \"name\": \"How often should I bump-test and calibrate it?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"Bump-test before each day of use; perform a full zero\/span calibration on the manufacturer's schedule or after any failed bump test.\"}}, {\"@type\": \"Question\", \"name\": \"How long do the sensors last?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"Electrochemical sensors generally last two to three years. Plan for replacement sensors and calibration gas as recurring costs.\"}}, {\"@type\": \"Question\", \"name\": \"What does it not detect?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"No VOCs, CO2 or specific toxics like ammonia or chlorine. For VOC work you need a PID; explore options across the Portable Gas Detectors hub.\"}}, {\"@type\": \"Question\", \"name\": \"Can one monitor cover a whole crew?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"No — it monitors the air where it is. For per-worker exposure, issue wearable clips from Personal \u0026 Wearable Gas Detectors; for a perimeter use Area \u0026 Transportable Gas Monitors.\"}}, {\"@type\": \"Question\", \"name\": \"Is it in stock?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"Use the Amazon buy button for live availability and delivery timing through our fulfillment partner.\"}}, {\"@type\": \"Question\", \"name\": \"Is this a fleet-management instrument?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"It is a capable field monitor. Sites needing automated docking-station bump\/cal across large fleets typically specify Industrial Scientific or BW Honeywell.\"}}]}, {\"@type\": \"Organization\", \"@id\": \"https:\/\/wcsafety.com\/#org\", \"name\": \"WC Safety\", \"url\": \"https:\/\/wcsafety.com\", \"logo\": \"https:\/\/wcsafety.com\/cdn\/shop\/files\/logo.png\"}, {\"@type\": \"Person\", \"@id\": \"https:\/\/wcsafety.com\/#editor\", \"name\": \"Steven Eaton\", \"jobTitle\": \"Editorial Lead\", \"worksFor\": {\"@id\": \"https:\/\/wcsafety.com\/#org\"}, \"knowsAbout\": [\"industrial gas detection\", \"confined-space atmospheric monitoring\", \"personal protective equipment\"]}, {\"@type\": \"Brand\", \"name\": \"Forensics Detectors\"}]}\n\u003c\/script\u003e","brand":"Forensics Detectors","offers":[{"title":"Default Title","offer_id":44266357031000,"sku":"B07J1WQST5","price":225.45,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0594\/1900\/0920\/files\/615YDnPc4_L._AC_SL1500.jpg?v=1782119869","url":"https:\/\/wcsafety.com\/products\/forensics-detectors-4-gas-monitor-usb-rechargeable","provider":"WC Safety","version":"1.0","type":"link"}