First Alert 10-Year Battery Slim Round Carbon Monoxide/Smoke Alarm With Voice Alert Combination photoelectric smoke and carbon monoxide alarm with 10-year battery helps protect homes from fire and dangerous carbon monoxide levels by providing up to a decade of uninterrupted monitoring. Comes equipped with dual sensors for reliable detection of two potentially deadly threats. If a threat is detected, the unit alerts you using audible signals, including a loud 85-decibel siren and a programmable voice alarm that indicates the type of threat and its location. A built-in 10-year lithium-ion battery provides continuous power for the lifetime of the alarm. Type Battery Operated, Voltage 3V, Battery Life 10 Yr. Battery, Sensor Type Photoelectric/Electrochemical, Dimensions 5.67 In. W. x 1 In. H. x 5.67 In. L., Battery Back-Up Battery Only, Alarm Type Smoke Carbon Monoxide, Decibel Level 85dB, Battery Type 3V Lithium Battery, Batteries Included Yes, Color White, UL Listed Yes, Warranty 10-Year Limited, Pkg Qty 1, Package Type Clamshell