10 year, battery & digital temperature display carbon monoxide detector, detects dangerous carbon monoxide for up to 10 years, uses an electrochemical carbon monoxide sensor to detect the carbon monoxide you can't see, smell, or taste in the air, built in 10 year lithium battery means you never need to worry about changing batteries during the lifetime of the alarm, designed to sit on top of a dresser or table top, has a backlit digital display that clearly shows the ambient temperature, as well as current & peak carbon monoxide concentrations, an 85 decibel horn sounds if carbon monoxide levels are too high, & a test/silence button silences the alarm & allows you to test its functionality.