Multi-Gas Monitors
Most confined-space permits and hazmat entry checklists begin with a multi-gas reading. This category holds the portable monitors that take it: 4-gas wearables such as the BW Clip4, GasAlert MicroClip X3 and RKI GX-3R, pumped samplers like the GasAlert Max XT II and mPower POLI MP400P, and configurable 5- and 6-gas platforms from Honeywell's MultiRAE line, Dräger's X-am series and GfG's Microtector.
Fire departments, hazmat teams, utilities and plant safety staff carry them for entry, leak response and personal monitoring. When they need calibration or repair, our San Antonio Repair Depot issues certificates tied to each instrument's serial number.
Featured Multi-Gas Monitors equipment
BW MicroClip XL
GX-3R
Honeywell BW Flex – Multi-Gas Detector with Bluetooth and i-Series Sensor Technology
Honeywell GasAlert MicroClip X3 – Compact 4-Gas Detector with IntelliFlash and 3-Year Sensor Life
X-am® 2800
BW Clip4
Gas-Rover w/ CO & O2 (VGC-301 / VGO-321)
GasAlert Max XT II
GasAlertQuattro
GOLD G3
GX-3R Pro
Honeywell BW Icon – 4-Gas Detector with Fixed 2-Year Life and Icon-Based Display
Honeywell BW Ultra – 5-Gas Detector for Confined Space Monitoring
Honeywell Flex 5 Series Modular Multi-Gas Detector
Honeywell GasAlert Quattro – Rugged Four-Gas Detector for Confined Space Entry and Industrial Safety
Honeywell MicroRAE – Wireless 4-Gas Diffusion Monitor for Connected Worker Safety
Honeywell MultiRAE Lite – Wireless One-to-Six Gas Monitor for VOCs, Combustibles & Toxic Gases
Honeywell MultiRAE Pro – Wireless Multi-Threat Gas Detector with Gamma Radiation Sensor
Honeywell MultiRAE – Wireless Six-Gas Monitor with PID, NDIR & Custom Sensor Options
Honeywell QRAE 3 – Wireless 4-Gas Monitor for Industrial and Emergency Response
Microtector II G450
Microtector II G460
Microtector III G888
POLI (MP400)
Choosing a multi-gas monitor
Four gases or more
A standard 4-gas monitor reads oxygen, combustibles (%LEL), carbon monoxide and hydrogen sulfide. That set covers most confined-space entries, and it is what the GasAlert Quattro, Honeywell MicroRAE, mPower POLI MP400 and BW Icon are built around. Add sensors when your hazards go further. The RKI GX-3R Pro and BW Ultra carry five gases. The QRAE 3 adds options such as SO2 and HCN. The MultiRAE offers 25+ sensor options, including PID and NDIR, and the GfG Microtector III G888 takes up to eight sensors. The Honeywell Flex 5 Series uses field-replaceable cartridges, so one base unit can run as a 4-, 5- or 6-gas detector. For lithium-ion battery incidents, the mPower POLI EV targets hydrogen and hydrogen fluoride. Our MultiRAE vs MultiRAE Lite vs MultiRAE Pro page compares the three RAE models side by side.
Diffusion or pumped
A diffusion monitor samples the air around the wearer, which suits all-shift personal monitoring. Testing a tank, manhole or vault before entry calls for a pump that pulls a sample through tubing while everyone stays outside. The GasAlert Max XT II and POLI MP400P have built-in pumps, the Dräger X-am 3500 samples remotely up to 147 feet, and the X-am 8000 runs in either pump or diffusion mode.
Connected or maintenance-free
Wireless models such as the MultiRAE, MicroRAE and QRAE 3 send readings and alarms to a safety officer or command post. Bluetooth units like the BW Flex and GX-3R Pro share data through a phone. At the simple end, the BW Clip4 and BW Icon run a fixed two-year life with no sensor or battery changes, which fits crews that prefer a wear-and-replace program.
What ownership involves
Plan for two routines. A bump test confirms the sensors and alarms respond. Calibration adjusts readings against certified gas. Keep calibration gas and regulators that match your sensor set. Our Repair Depot calibrates and repairs multi-gas monitors with a 48–72 hour typical turnaround, and as a Honeywell Authorized Service Provider we perform warranty service on BW and RAE Systems monitors. Agencies can buy through BuyBoard or PCA without a separate bid.
Frequently asked questions
What gases does a 4-gas monitor detect?
A 4-gas monitor measures oxygen (O2), combustible gases as a percentage of the lower explosive limit (%LEL), carbon monoxide (CO) and hydrogen sulfide (H2S). Together they cover the most common confined-space hazards: oxygen deficiency or enrichment, flammable atmospheres and the two toxic gases most often found in tanks, sewers and vaults. The Honeywell GasAlert Quattro and Honeywell MicroRAE are examples built around this sensor set.
What is the difference between a 4-gas monitor and a multi-gas monitor?
A 4-gas monitor is one kind of multi-gas monitor, set up for O2, LEL, CO and H2S. Multi-gas also includes 5- and 6-gas instruments that add a photoionization detector for VOCs, or sensors for CO2, SO2, HCN and other toxic gases. Configurable models such as the Honeywell MultiRAE and Dräger X-am 8000 can be fitted for the specific hazards a site or hazmat team expects to meet.
What is a bump test on a gas detector?
A bump test briefly exposes a gas detector to a known concentration of test gas to confirm that each sensor responds and every alarm activates. It does not change the readings; calibration does that. Common practice is to bump test before each day's use. A monitor that fails a bump test should be calibrated or sent for service before anyone relies on it for entry or personal protection.
How often should a multi-gas monitor be calibrated?
Calibrate on the interval in the manufacturer's manual and your safety program, and again whenever the monitor fails a bump test, takes a hard impact or sees a high gas exposure. Each calibration should be documented. FarrWest's Repair Depot issues calibration certificates tied to the instrument's serial number, and its Service Program can handle calibration on-site on a cycle between 30 and 180 days.
What is the best multi-gas detector for confined space entry?
The right detector depends on how the space is tested and worked. Pre-entry testing needs a pump so you can sample before anyone goes in, as on the Honeywell GasAlert Max XT II, mPower POLI MP400P or Dräger X-am 3500. Continuous monitoring inside calls for a wearable 4-gas diffusion unit such as the GasAlert MicroClip X3 or RKI GX-3R. Add a PID or extra toxic sensors if the space held fuels, solvents or process chemicals.
How much does a 4-gas monitor cost?
Price depends on sensor count, pumped versus diffusion sampling, wireless features and whether the unit is a fixed-life disposable or a serviceable instrument. Lifetime cost also includes replacement sensors, calibration gas and service. On FarrWest.com some compact 4-gas models can be ordered online at a listed price, while configured and wireless instruments are quoted through the quote request form.