... leak leakage concentrations reach concentrations, when the alarm set out, sound-light alarm detector, and the launch of the platoon or ... the aging, poisoning, avoid misstatement, omission.· Can independent alarm, also can with the security system, the village intelligence system ... Specifications· Detect principle:semiconductor· Detected gasNG,LPG,MG· alarm concentration:NG:4%LEL±3%LELLPG:7%LEL±3%LELMG ...