gas detector 1)Ranges:Sensor dependent ... LEL,%VOL Programmable alarm operation value 4-20mA Smart Toxic Gas DetectorTechnical features * 4-20mA, 2 wire connection ... * Multi-parameter backlight LCD display: measuring range,digital gas reading ,units, bar graph , system status etc.* ... O2,CO and combustible gas. Stainless steel for others. * IP rating: Ip66 Smart Toxic Gas Detector with alarm operation ...