The First Alert CO710 Carbon Monoxide Alarm with 10-Year Battery and Digital Temperature Display detects dangerous carbon monoxide for up to 10 years. This carbon monoxide detector uses an electrochemical carbon monoxide sensor, the most accurate CO detection technology available, to detect the CO you can't see, smell, or taste in the air. A built-in 10-year lithium battery means you never need to worry about changing batteries during the lifetime of the alarm. This stylish CO monitor is designed to sit on top of a dresser or tabletop, and it has a backlit digital display that clearly shows the ambient temperature, as well as current and peak CO concentrations. An 85-decibel horn sounds if carbon monoxide levels are too high, and a test/silence button silences the alarm and allows you to test its functionality.