Starting at $1,270.00
  • Usually ships in 4-6 weeks



  • LEL, O2, H2S, CO, CO2 & 100% vol CH4
  • Many toxic gases including NH3, SO2 & HCN
  • Infrared sensor for combustibles & CO2
  • Explosion proof options
  • 35 second or less response time
  • 10-30VDC operating voltage
  • 4-20mA & digital Modbus outputs
  • Available approval ratings:
    • UL, cULus, CSA, cCSAus
    • Radio frequency resistent CSA
  • 2 fully programmable alarm relays & fail relay
  • Non-intrusive calibration via magnetic wand
  • Water repellent sensor cover
  • Available as remote or direct mount
    • Remote mount includes calibration adapter

What's in the Box

  • Junction box


The RKI Instruments M2A gas transmitter operates as a stand alone gas monitor or as part of an integrated system. It connects to any controller, PLC, or DCS with an analog or digital signal. It can be calibrated externally with a magnetic wand, avoiding the need to open the housing and declassify an area for routine maintenance. Automatic zero drift correction compensates for aging sensors and ensures stable readings.

Sensor construction is rated Class I, Div 1 Groups B, C, D for flammables, CO, H2S, O2, and CO2, and Class I, Div 2 for all other toxics. Toxic sensors are electrochemical type plug-in sensors, providing high specificity, fast response, and a long life. Their plug-in design allows quick replacement in the field without tools. Sensors are available for NH3, SO2, PH3, AsH3, and HCN.

Applications for the RKI Instruments M2A include petrochemical plants, refineries, water and wastewater treatment plants, pulp and paper mills, manufacturing facilities, automotive, semiconductor and chemical plants.


Here's how some of our customers use this product...

Monitoring Hydrogen Gas

The Background: Our customer is a manufacturing facility that uses hydrogen gas in their manufacturing process. They seek a means to monitor their hydrogen storage tanks for leaks.

The Problem: Our customer stores their supply of hydrogen gas in large tanks which are in the general proximity of high voltage equipment. Hydrogen is highly flammable and even small leaks can accumulate enough gas to result in an explosion if it comes into contact with a spark from the high voltage equipment. The customer wants a way to monitor for leaks remotely.

The Solution: We recommended the RKI Instruments M2A gas transmitter, a fixed mount detector that continuously monitors & displays gas concentration as a stand-alone monitor or as part of a system. Since hydrogen is lighter than air, the sensor was mounted up high and wired to an eye-lkevel display so the display could be easily seen.

O2 Level Detection

The Background: Our customer is a large metal fabricator with multiple welding booths. They seek a means of monitoring the oxygen levels inside each booth.

The Problem: The customer uses argon as a shielding gas during the welding process. Since argon can displace oxygen in the welding booth, it is important to monitor oxygen levels to ensure they are above a minimum threshold.

The Solution: We recommended the RKI Instruments M2A gas transmitter which can be used as a stand-alone gas monitor or as part of an integrated system. The M2A includes internal relays to trigger a visual or audible alarm if the oxygen levels below the preset limit.