Forensics Detectors 4 Gas Monitor with Pump (NIST, Confined-Space Probe)

Forensics Detectors 4 Gas Monitor with Pump — Pre-Entry Sample-Draw

The Forensics Detectors 4 gas monitor with pump is the pre-entry tool of the family — a portable gas detector with a motorized pump and probe that draws a sample from a sealed space so you can test oxygen (O2), combustible gas (LEL), carbon monoxide (CO) and hydrogen sulfide (H2S) before anyone goes in. It ships NIST-calibrated.

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The Forensics Detectors 4 Gas Monitor with Pump is a NIST-calibrated, electrochemical four-gas instrument (O2, CO, H2S, LEL) with a motorized sample-draw pump and probe for confined-space pre-entry testing.

Key features

• Built-in motorized pump and probe to draw a remote sample before anyone enters a space
• Monitors oxygen (O2), combustible gas (LEL), carbon monoxide (CO) and hydrogen sulfide (H2S) — the confined-space hazard set — with a NIST certificate
• Tests the bottom of a tank, vault or manhole from the surface
• Audible, vibration and visual alarms with adjustable set points
• USB-rechargeable for shift-long readiness
• The pre-entry tool in the Forensics four-gas family

Specifications

Where the Forensics Detectors 4 Gas Monitor with Pump fits

• Confined-space pre-entry sampling
• Tank, vessel and vault testing from the surface
• Sewer and manhole pre-entry checks
• Emergency-response atmosphere assessment
• Permit-entry programs requiring remote sampling

What the Forensics Detectors 4 Gas Monitor with Pump detects (and what it doesn’t)

It measures oxygen (O2), combustible gas (LEL), carbon monoxide (CO) and hydrogen sulfide (H2S) and uses a motorized pump with a probe to sample remotely — its key advantage over diffusion meters like the Forensics 4 Gas Meter. It does not detect VOCs, CO2 or single toxics such as chlorine; those need a PID or dedicated sensor. Keep the pump and probe clean, bump-test with four-gas calibration gas, and calibrate on schedule. For all-shift wear after entry is cleared, add a clip from Personal & Wearable Gas Detectors; for ongoing area coverage during the job, see Area & Transportable Gas Monitors.

Cross-shopping? This unit sits in our Portable Gas Detectors hub alongside the Forensics Detectors 4 Gas Meter, Forensics Detectors USB 4 Gas Monitor, TopTes Guard-863Pro, TopTes Guard-101. If one worker needs all-shift wear instead of a carried meter, see Personal & Wearable Gas Detectors; for a fixed install or a job-site perimeter, see Fixed Gas Detection Systems and Area & Transportable Gas Monitors.

Forensics Detectors 4-gas family compared

• Choose this 4 Gas Monitor with Pump when you must sample a space before entry.
• Pick the USB 4 Gas Monitor for ongoing monitoring without remote sampling.
• Pick the 4 Gas Meter for the lightest, lowest-cost diffusion option.

Frequently asked questions

Why choose a 4 gas monitor with a pump?

A pump lets you draw a sample from a sealed or remote space — the bottom of a tank, vault or manhole — so you can test the atmosphere before anyone enters. Diffusion meters can only read the air around them.

What gases does it detect?

It reads oxygen (O2), combustible gas (LEL), carbon monoxide (CO) and hydrogen sulfide (H2S) with a NIST certificate. For VOCs you need a separate PID; see the Portable Gas Detectors hub.

Is the pump monitor NIST calibrated?

Yes — it ships with a USA NIST calibration certificate. Bump-test before each use and calibrate on the manufacturer's schedule.

How long is the probe and how do I use it?

The unit includes a probe you lower into the space; the motorized pump draws the sample up to the sensors. Follow the manufacturer's pre-entry testing sequence: oxygen first, then combustibles, then toxics.

How does it compare to the diffusion Forensics meters?

It adds a motorized pump and probe over the 4 Gas Meter and USB 4 Gas Monitor, at a higher price — choose it specifically when remote sampling is required.

Is it good for permit-required confined spaces?

Yes — remote sampling before entry is exactly what permit-entry programs need, and its O2/CO/H2S/LEL set matches OSHA 1910.146 hazards.

How is it powered?

It uses a USB-rechargeable battery sized for shift-long use, including pump operation during sampling.

Does the pump need maintenance?

Yes — keep the pump and probe clean and clear of moisture and debris, and check pump flow per the manufacturer's instructions so samples draw correctly.

What alarms does it have?

Audible, vibration and visual alarms with adjustable set points trigger when a gas exceeds its threshold.

What does it not detect?

No VOCs, CO2 or specific toxics like ammonia or chlorine. For VOC work, a PID is required — explore the Portable Gas Detectors hub.

Is it in stock?

Use the Amazon buy button for live availability and delivery timing through our fulfillment partner.

Do I still need a personal monitor with this?

Often yes — the pump unit handles pre-entry and shared testing, while each worker can wear a clip from Personal & Wearable Gas Detectors for personal exposure once inside.