{"product_id":"forensics-mini-4-gas-monitor","title":"Forensics Mini 4 Gas Monitor — Compact O2, CO, H2S \u0026 LEL (NIST)","description":"\u003c!-- PRODUCT B0GNQGL4NY | 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 mini 4 gas monitor is one of the 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 with the \u003ca href=\"\/products\/forensics-voc-detector\" title=\"Forensics VOC Detector\"\u003eForensics VOC Detector\u003c\/a\u003e below before you order.\u003c\/div\u003e\n\n\u003ch2 id=\"top\"\u003eForensics Mini 4 Gas Monitor — Compact O2, CO, H2S \u0026amp; LEL\u003c\/h2\u003e\n\n\u003cp\u003eThe \u003cstrong\u003eForensics mini 4 gas monitor\u003c\/strong\u003e packs O2, CO, H2S and LEL into a compact, NIST-calibrated body — a \u003ca href=\"\/collections\/portable-gas-detectors\" title=\"portable gas detector\"\u003eportable gas detector\u003c\/a\u003e for crews who want full four-gas coverage in the smallest, easiest-to-carry form, with a top 4.8-star rating.\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 Mini 4 Gas Monitor is a compact, NIST-calibrated, USB-rechargeable confined-space monitor for O2, CO, H2S and combustible LEL.\u003c\/p\u003e\n\n\u003ch3 id=\"features\"\u003eKey features\u003c\/h3\u003e\n\n\u003cul\u003e\n\u003cli\u003eReads all four confined-space gases — O2, CO, H2S and LEL — in a compact body\u003c\/li\u003e\n\u003cli\u003eUSA NIST-traceable calibration for documented accuracy\u003c\/li\u003e\n\u003cli\u003eUSB-rechargeable for shift-long use\u003c\/li\u003e\n\u003cli\u003eSmaller and lighter than standard 4-gas meters for easy carry\u003c\/li\u003e\n\u003cli\u003eAudible, visual and vibration alarms\u003c\/li\u003e\n\u003cli\u003eStrong 4.8-star rating\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\u003eCompact, easy to carry\u003c\/li\u003e\n\u003cli\u003eNIST-calibrated\u003c\/li\u003e\n\u003cli\u003eUSB-rechargeable\u003c\/li\u003e\n\u003cli\u003eAffordable 4-gas\u003c\/li\u003e\n\u003cli\u003eExcellent 4.8-star rating\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 only (no pump)\u003c\/li\u003e\n\u003cli\u003eNo VOC\/PID coverage\u003c\/li\u003e\n\u003cli\u003eSmaller display than full-size units\u003c\/li\u003e\n\u003cli\u003eSensors need periodic replacement\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;\"\u003eForm\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:8px 10px;border:1px solid #3a3a3a;\"\u003eMini \/ compact\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;\"\u003eUSA NIST-traceable\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\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, visual \u0026amp; vibration\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\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:8px 10px;border:1px solid #3a3a3a;\"\u003eElectrochemical + catalytic\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003c\/div\u003e\n\n\u003ch3\u003eWhere the Forensics Mini 4 Gas Monitor fits\u003c\/h3\u003e\n\n\u003cul\u003e\n\u003cli\u003eConfined-space entry monitoring\u003c\/li\u003e\n\u003cli\u003eField and utility work\u003c\/li\u003e\n\u003cli\u003eMaintenance rounds\u003c\/li\u003e\n\u003cli\u003eBackup\/spare 4-gas in a kit\u003c\/li\u003e\n\u003cli\u003eGeneral multi-gas spot checks\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2 id=\"compatibility\"\u003eWhat the Forensics Mini 4 Gas Monitor detects (and what it doesn’t)\u003c\/h2\u003e\n\n\u003cp\u003eIt monitors \u003cstrong\u003eO2, CO, H2S and combustible LEL\u003c\/strong\u003e — not VOCs, CO2 or specific toxics. For VOCs use the \u003ca href=\"\/products\/forensics-voc-detector\" title=\"Forensics VOC Detector\"\u003eForensics VOC Detector\u003c\/a\u003e; for single toxics the \u003ca href=\"\/products\/forensics-chlorine-analyzer-cl2\" title=\"Chlorine\"\u003eChlorine\u003c\/a\u003e or \u003ca href=\"\/products\/forensics-ammonia-detector-nh3\" title=\"Ammonia\"\u003eAmmonia\u003c\/a\u003e analyzers. It is diffusion; for remote pre-entry sampling use the \u003ca href=\"\/products\/forensics-detectors-4-gas-monitor-with-pump\" title=\"Forensics 4 Gas + Pump\"\u003eForensics 4 Gas + Pump\u003c\/a\u003e. Compared with the \u003ca href=\"\/products\/forensics-detectors-4-gas-meter-confined-space\" title=\"4 Gas Meter\"\u003e4 Gas Meter\u003c\/a\u003e it is more compact. Bump-test before use.\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 \u003ca href=\"\/products\/forensics-voc-detector\" title=\"Forensics VOC Detector\"\u003eForensics VOC Detector\u003c\/a\u003e, \u003ca href=\"\/products\/amprobe-co2-100-carbon-dioxide-meter\" title=\"Amprobe CO2-100\"\u003eAmprobe CO2-100\u003c\/a\u003e, \u003ca href=\"\/products\/forensics-ammonia-detector-nh3\" title=\"Forensics Ammonia Detector\"\u003eForensics Ammonia Detector\u003c\/a\u003e, \u003ca href=\"\/products\/forensics-chlorine-analyzer-cl2\" title=\"Forensics Chlorine Analyzer\"\u003eForensics Chlorine Analyzer\u003c\/a\u003e. For other gas-detection form factors see \u003ca href=\"\/collections\/personal-gas-detectors\" title=\"Personal \u0026amp; Wearable Gas Detectors\"\u003ePersonal \u0026amp; Wearable Gas Detectors\u003c\/a\u003e, \u003ca href=\"\/collections\/fixed-gas-detection-systems\" title=\"Fixed Gas Detection Systems\"\u003eFixed Gas Detection Systems\u003c\/a\u003e, \u003ca href=\"\/collections\/area-gas-monitors\" title=\"Area \u0026amp; Transportable Gas Monitors\"\u003eArea \u0026amp; Transportable Gas Monitors\u003c\/a\u003e, or browse the full \u003ca href=\"\/collections\/gas-detectors\" title=\"Gas Detectors\"\u003eGas Detectors\u003c\/a\u003e range.\u003c\/p\u003e\n\n\u003ch2 id=\"comparison\"\u003ePortable 4-gas options 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;\"\u003ePortable 4-gas options (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;\"\u003eBrand\u003c\/th\u003e\n\u003cth style=\"color:#ffb74d;padding:9px;border:1px solid #3a3a3a;text-align:left;\"\u003eNotable\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-mini-4-gas-monitor\" title=\"Forensics Mini 4 Gas\"\u003eForensics Mini 4 Gas\u003c\/a\u003e\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:9px;border:1px solid #3a3a3a;\"\u003eForensics\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:9px;border:1px solid #3a3a3a;\"\u003eCompact, NIST, USB\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:9px;border:1px solid #3a3a3a;\"\u003e~$295\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-meter-confined-space\" title=\"Forensics 4 Gas Meter\"\u003eForensics 4 Gas Meter\u003c\/a\u003e\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:9px;border:1px solid #3a3a3a;\"\u003eForensics\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:9px;border:1px solid #3a3a3a;\"\u003eLightest, NIST\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 style=\"background:#2a2520;\"\u003e\n\u003ctd style=\"color:#e0e0e0;padding:9px;border:1px solid #3a3a3a;\"\u003e\u003cstrong\u003e\u003ca href=\"\/products\/ato-handheld-4-gas-detector\" title=\"ATO 4 Gas Detector\"\u003eATO 4 Gas Detector\u003c\/a\u003e\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:9px;border:1px solid #3a3a3a;\"\u003eATO\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:9px;border:1px solid #3a3a3a;\"\u003eSound\/light\/vibration\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:9px;border:1px solid #3a3a3a;\"\u003e~$449\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 the \u003cstrong\u003eMini 4 Gas Monitor\u003c\/strong\u003e for the most compact NIST-calibrated four-gas at a low price.\u003c\/li\u003e\n\u003cli\u003eWant the lightest standard meter? See the \u003ca href=\"\/products\/forensics-detectors-4-gas-meter-confined-space\" title=\"Forensics 4 Gas Meter\"\u003eForensics 4 Gas Meter\u003c\/a\u003e.\u003c\/li\u003e\n\u003cli\u003eNeed a pump? Use the \u003ca href=\"\/products\/forensics-detectors-4-gas-monitor-with-pump\" title=\"Forensics 4 Gas + Pump\"\u003eForensics 4 Gas + Pump\u003c\/a\u003e.\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 mini 4 gas monitor measure?\u003c\/h3\u003e\u003cp\u003eO2, CO, H2S and combustible LEL — the confined-space set. For VOCs use the \u003ca href=\"\/products\/forensics-voc-detector\" title=\"Forensics VOC Detector\"\u003eForensics VOC Detector\u003c\/a\u003e.\u003c\/p\u003e\n\u003ch3\u003eHow is it different from the standard 4 Gas Meter?\u003c\/h3\u003e\u003cp\u003eIt is more compact and USB-rechargeable; the \u003ca href=\"\/products\/forensics-detectors-4-gas-meter-confined-space\" title=\"Forensics 4 Gas Meter\"\u003eForensics 4 Gas Meter\u003c\/a\u003e is the lightest standard meter. Both are NIST-calibrated.\u003c\/p\u003e\n\u003ch3\u003eIs it NIST calibrated?\u003c\/h3\u003e\u003cp\u003eYes — USA NIST-traceable calibration. Bump-test before use and recalibrate on schedule.\u003c\/p\u003e\n\u003ch3\u003eIs it rechargeable?\u003c\/h3\u003e\u003cp\u003eYes — USB-rechargeable, sized for a full work shift.\u003c\/p\u003e\n\u003ch3\u003eCan I use it for confined-space entry?\u003c\/h3\u003e\u003cp\u003eYes for monitoring the four hazards. For pre-entry sampling, use the \u003ca href=\"\/products\/forensics-detectors-4-gas-monitor-with-pump\" title=\"Forensics 4 Gas + Pump\"\u003eForensics 4 Gas + Pump\u003c\/a\u003e.\u003c\/p\u003e\n\u003ch3\u003eDoes it have a pump?\u003c\/h3\u003e\u003cp\u003eNo — it is diffusion. For remote sampling choose the \u003ca href=\"\/products\/forensics-detectors-4-gas-monitor-with-pump\" title=\"pump model\"\u003epump model\u003c\/a\u003e.\u003c\/p\u003e\n\u003ch3\u003eWhat alarms does it have?\u003c\/h3\u003e\u003cp\u003eAudible, visual and vibration alarms trigger when any of the four gases exceeds its set point.\u003c\/p\u003e\n\u003ch3\u003eWhat does it not detect?\u003c\/h3\u003e\u003cp\u003eVOCs, CO2 and specific toxics. For VOCs use the \u003ca href=\"\/products\/forensics-voc-detector\" title=\"VOC Detector\"\u003eVOC Detector\u003c\/a\u003e; for chlorine the \u003ca href=\"\/products\/forensics-chlorine-analyzer-cl2\" title=\"Chlorine Analyzer\"\u003eChlorine Analyzer\u003c\/a\u003e.\u003c\/p\u003e\n\u003ch3\u003eWhy is it rated so highly?\u003c\/h3\u003e\u003cp\u003eIt pairs compact size, NIST calibration and USB charging at a low price, earning a strong 4.8-star rating.\u003c\/p\u003e\n\u003ch3\u003eIs it in stock and how does it ship?\u003c\/h3\u003e\u003cp\u003eUse the Amazon buy button for current availability and delivery timing through our fulfillment partner.\u003c\/p\u003e\n\u003ch3\u003eHow long do the sensors last?\u003c\/h3\u003e\u003cp\u003eElectrochemical and catalytic sensors typically last two to three years; budget for replacement sensors and calibration gas.\u003c\/p\u003e\n\u003ch3\u003eIs it a good backup unit?\u003c\/h3\u003e\u003cp\u003eYes — its compact size and low price make it a popular spare\/backup 4-gas to keep in a kit or truck.\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 mini 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\/B0GNQGL4NY?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 here are taken from the manufacturer’s published listing for Forensics Mini 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 and \u003ca href=\"https:\/\/www.osha.gov\/annotated-pels\" rel=\"noopener\" target=\"_blank\" style=\"color:#4fc3f7;\"\u003eOSHA Permissible Exposure Limits\u003c\/a\u003e. Disclosed: WC Safety earns Amazon affiliate commissions on outbound clicks; that does not influence the specs shown or 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: atmospheric monitoring, 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 and \u003ca href=\"https:\/\/www.osha.gov\/annotated-pels\" rel=\"noopener\" target=\"_blank\" style=\"color:#4fc3f7;\"\u003eOSHA PELs\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-mini-4-gas-monitor#product\", \"name\": \"Forensics Mini 4 Gas Monitor — Compact O2, CO, H2S \u0026 LEL (NIST)\", \"description\": \"Forensics mini 4 gas monitor — compact, NIST-calibrated O2, CO, H2S \u0026 LEL detector with USB recharge for confined-space and field use. 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