First Alert Dual-Sensor Smoke Fire Alarm Smoke alarm with dual sensing technology and nuisance resistance utilizes two different technologies capable of quickly deciphering between flaming and smoldering fires. Equipped with dual photoelectric and ionization smoke sensing technologies. A single button silences and tests the smoke detector for simple operation. Battery powered, easy to install anywhere, no wiring required. Battery life varies according to use and application. UL Underwriter's Laboratories listed. Type Battery Operated, Voltage 3V, Battery Life Varies According To Application, Sensor Type Photoelectric/Ionization, Dimensions 5 In. W. x 2 In. H. x 5 In. L., Battery Back-up Battery Only, Alarm Type Smoke, Decibel Level 85dB, Battery Type AA Batteries, Batteries Included Yes, Color White, UL Listed Yes, Warranty 10-Year Limited, Pkg Qty 1, Package Type Clamshell