This smoke and CO alarm is equipped with reliable and long-lasting sensors that ensure 10 years of stable performance, keeping your home and family safe for a decade A built-in LCD allows you to see any changes in the levels of carbon monoxide in your home and the devices battery status; to save power, it will only activate when tested, or if the CO ppm reaches a certain level for a certain period of time This battery-powered combination smoke and carbon monoxide alarm uses both photoelectric and electrochemical sensors to protect you and your loved ones against smoke and dangerous CO levels, keeping your home and family safe for a decade When the device is triggered, its siren exceeds 85 dB at 10 ft (3 m) to ensure that it wakes up even the deepest sleepers This device only measures 5 1.4 in (128 34.7 mm) and comes in a thin and light design; with the accessories included, it is easy to install, without the need to hire an electrician