Smoke Alarm, Battery Location Sealed, Battery Locking Pin Yes, Battery Size 9V, Detector Type Smoke/CO Detector, Features Patented Quick Find Alarm Origination Feature easily identifies the first alarm to sound in an interconnected system. Single Test/Silence Button. Easy Installation and Fewer Callbacks. 10 Year Product End-of-Service Warning. Tamper Alarm & Battery. Meets UL, NFPA, FHA, HUD, and California State Fire Marshal Standards, Includes Dust Cover, Power Source Hardwired