The product is wall mounted compound gas&CO detector with high stability (hereinafter called detector). It is used for detecting leaking gas and CO.Advanced semiconductor sensor is adopted to ensure high stability and long life. It is convenient for mounting.Built-in MCU connected to I/O of all kinds of functional modules,with its program written in the MCU to coordinate all the modules work properly,stable and reliable.The product is suitable for the safety of residential house, villas,hotels, markets, boarding house etc.