Carbon Monoxide Alarm Battery Chemistry Alkaline Battery Location Back Battery Locking Pin No Battery Size Not Applicable Detector Type CO Detector Features Compact Plug-In Design Covers Only One Outlet. Large Bright Display Screen. Peak Memory Recall. 7 Year Product End-of-Service Warning. Meets UL NFPA FHA and HUD Standards Includes Plug-in Design Cover Power Source Hardwired Sensor Type Metal Oxide Semiconductor Visual Alert Type Digital Display LED Volume Level 85 dB @ 10 ft