... Unit:ppm, mA, %,%LEL,%VOL 4)Humidity:10-95%RH CO2 gas detector Technical features* 4-20mA, 3 wire connection ,compatible ... with existing alarm control unit or DCS (Distributed Control System) * Flameproof body design acc. to IEC61508,simple and easy ... display: measuring range,digital gas reading ,units, bar graph , system status etc.* International standard plug-in sensor, Plug and Play ...