Starting at $560.00
  • Usually ships in 7-10 business days



  • Non-toxic gases include
    • LEL, H2S, CO, PPM H2, & CO2
  • Toxic gases include
    • NH3, AsH3, Cl2, ClO2, HCN & SO2
  • Infrared sensor for combustibles & CO2
  • Hydrogen-specific now available
  • Patented water-repellent sensor coating
  • 4-20 mA output
  • Explosion proof construction
  • Optional stainless steel junction box


The RKI Instruments S2 Series diffusion sensor / transmitter are available for LEL, H2-specific (LEL and ppm), oxygen, H2S, CO and for a variety of toxic gases. Available in both non-explosion proof and explosion-proof housing, dependent on gas(es) required, the S2 Series are designed to interface with RKI controls or with PLC/DCS systems as remote sensors.

RKI Instruments S2 Series units detecting LEL, H2-specific, oxygen, H2S, CO2 and CO feature an explosion-proof housing with flame arrestors and are approved for use in hazardous areas (Class l, Groups B, C, D). The non-explosion proof versions of these RKI Instruments sensors / transmitters are available for oxygen, H2S, CO and CO2 and designed for use in non-hazardous areas. LEL sensors are available using catalytic bead and infrared technologies.

These RKI Instruments units can be used either indoors or outdoors and the flame arrestors in the explosion-proof versions utilize a patented coating which make them water repellent. Additionally, splash guards are available for use in very wet environments and an optional stainless steel junction box is available for corrosive environments.