Watts Industries. GSX gas alarm unit. Gas alarm unit with built-in sensor. Visual and audible alarm. With relay for the control of one or more NC (or NO) solenoid valves. The GSX can operate as a separate unit but also allows detection in up to 11 different rooms, in which case the network is programmed according to the Master-Slave system. 2 alarm levels (10% LEL and 15% LEL). 2 models: "MET" (methane, natural gas) and "LPG" (LPG, propane, butane).