... :ppm, mA, %,%LEL,%VOL 4)Humidity:10-95%RH CO2 gas detector Technical features* 4-20mA, 3 wire connection ,compatible ... maintenance. * Multi-parameter backlight LCD display: measuring range,digital gas reading ,units, bar graph , system status etc.* International standard ... %,%LEL,%VOL* Operating temperature: -40~70°C (According to gas sensor operating conditions)* Humidity: 10-95%RH (non condensing)* Ex ...