First Alert CO710 10-Year Battery Electrochemical Carbon Monoxide Alarm with Digital Temperature Display provides convenient and reliable carbon monoxide protection. This carbon monoxide detector does not require installation - simply place on a tabletop or shelf throughout your home or with you on the go. The built-in 10-year lithium battery means you don't need to worry about changing batteries or low battery chirps during the lifetime of the detector. This stylish CO monitor also has a backlit digital display that shows temperature and CO concentration when detected. Uses an advanced electrochemical CO sensor to detect elevated carbon monoxide levels. When CO is detected, the carbon monoxide detector sounds an alarm to warn you of the threat. The backlit LED display can be changed to show the ambient room temperature as well as current CO concentrations and recent peak CO levels in parts per million. In the event of a CO incident, the data stored from the peak function can provide valuable information to emergency or hospital staff. Features a built-in 10-year lithium metal battery, so you never need to worry about replacing batteries during the lifetime of the unit. An end-of-life timer lets you know when the device should be replaced. When carbon monoxide levels rise, the carbon monoxide detector sounds an 85-decibel siren that is designed to wake even the soundest of sleepers. A single button allows you to silence the alarm, as well as test to ensure the alarm is working properly.