The Stand-Alone Gas Leakage Detector is an INPUT DEVICE designed for natural gas,LPG detection. It can use independently. Upon detection of natural gas and LPG, the GL-01 automatically generates sound flash alarm. The unit is RF and EMI Immunity to interferences produced by radio device. Operating voltage: 85-265V AC; Wall mounted; 30ppm,Alarms Not Activate Within 120minutes 50ppm, Alarms Within 60~90 minutes 100ppm, Alarms Within 10~40 minutes 300ppm, Alarms Within 3 minutes Dimension: 115*72*45mm . Alarm output: Independent: Sound Flash alarm; Network: Sound Flash alarm;Relay output; Wireless: Sound Flash alarm;RF signal sensor life:5 years Applications For indoor use.