Working voltage: AC220V Wireless transmitting distance: 100m Transmitting frequency : 315MHz +/- 0.75MHz Gas Alarm system, Home Safe System WB-702K Feature:1. Use good gas ... light alarm or wireless cable compatible alarm is optional.4. Can be used alone, work with networking control system, or connect with ... more details, pls feel free to contact us! Gas Alarm system, Home Safe System WB-702K