... and close the gas valve 3,Alarm,security HOT!lpg gas detector with shut off valve Features:Adopts ... for using together with many low voltage control system (burglar alarms, building talkback system and tri-meters reading transmission). High stability ... renew automatically.Parameters: Gas detectedcoal gas ,natural gas ,LPG(liquefied petroleum gas)SensorNew Nanotechnology sensor, super long working ...