Four-Gas Detector (H2S, CO, O2, Flammable, Peak Read )

GAO Tek Four-Gas Detector provides field professionals the ability to detect four gases H2S, CO, O2 and flammable gas with Peak reading feature.



GAOTek’s Four Gas Detector is a high quality and durable instrument which can be used in all kinds of toxic environments. It is widely used to monitor O2, CO, H2S, and combustible gases. The device weighs only 0.54 lbs (244g) and highlights four key operations which makes them
easy to use. The instrument contains an additional alarm function which allows them to vibrate and warns users of any bad situation (i.e. noisy workplaces). Moreover, the device features a big LCD display which provides real-time monitoring as well as a quick calibration function that can save up to 75 hours of data. The apparatus also comes with a rechargeable lithium ion battery which can last up to 18 hours. With its small shape and affordable price, GAOTek’s Four Gas Detector is an ideal choice that should be included in every technician’s toolkit.

Key Features

  • Various Uses: 1-4 kinds of gas monitoring (O2, H2S, CO, LEL)
  • Large Data Storage: 75 hours data record ability
  • Portability: Small volume, light weight, durable ABS chassis
  • Readability: Graph form liquid crystal display
  • Variety of Signals: Visual, vibration, and auditory alarm
  • Efficient Device: Quick calibration
  • Well Powered: Lithium ion battery

Technical Specifications

Shell High strength, impact resistant, composite material-resistant to RFI and electromagnetic interference (EMI)
Overall size 4.29 x 2.45 x 1.37 in (10.9cm x 6.22cm x 3.48cm)
Weight 0.54 lbs (244g);0.72 lbs (326g)(With pump)


M40 have 1, 2, 3 or 4 gas configuration optional,

Including oxygen, hydrogen sulphide, carbon monoxide (electrochemical sensor)

Range Gas Symbols Range Resolution
Carbon monoxide CO 0-999ppm 1 ppm
Hydrogen sulfide H2S 0-500ppm 1 ppm
oxygen O2 0-30%Vol 0.1%
Flammable gas LEL 0-100%LEL 1%
Power supply Rechargeable lithium ion batteries
Running time 18 hours – The instrument (no alarm) 12 hours – Instrument with pump (no alarm)
Monitor Big font, high contrast characters, graphic symbols and unique amber light can be in the background of weak light environment to provide clear mandible
Alarm device Vibration alarm, 90 decibels and the lights on sound and light alarm.

High/low concentration alarm, short-term exposure limit alarm, time weighted average alarm and low battery quantity alarm.

Data record Can record up to 75 hours of data
Temperature range 4°F to 122°F (-20º to 50ºC)
Humidity range 15 ~ 95% RH (conventional), 0 ~ 99% RH (intermittent) (non-condensable)
Protection level IP65
The authentication UL laboratory (UL)-1 class, I class, A, B, C, D group; T4

Canadian standards association (CSA)-1 class, I class, A, B, C, D group; T4

Cenelec (ATEX)-EEx ia d IIC T4

Australia-Ex ia s Zone 0 IIC China metrology, explosion-proof authentication T4