Product function description: Inadequate indoor combustion of gas stove/gas water heater/honeycomb briquette/charcoal may produce carbon monoxide, and high concentration may cause or death. When the carbon monoxide alarm detects that the concentration of carbon monoxide in the air exceeds the standard, it will give an alarm sound of 80 decibels until the concentration is lower than the dangerous value. It can also linkage exhaust fan and exhaust fan. Valves, window openers and other equipment shall enhance indoor ventilation. Carbon Monoxide Alarm Communication protocol: WiFi Compatible with for tuya APP It can linkage valves, exhaust fans, lights, switches, sirens and other equipment Detection gas: CO Alarm mode: 80 dB on-site alarm/APP alarm/SMS/telephone alarm Power supply mode: USB power cord is often used for power supply without built-in battery. There may be slight color difference or difference between the actual product and the actual product. Material: plastic colour: Gray Package Contents: 1 x carbon monoxide alarm Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.