Battery operated -- easy installation on walls or ceilings / 85 decibel alarm / Test - Reset button / Green light when operating # Features a low profile design, installs easily with no wiring required # Updates every 15 seconds # Operates on 3 AA Batteries (included) # Test / Reset button silences the alarm, and can alternately be used to test the alarm's electronics # Green light indicates when operating # Special 85 decibel alarm sounds when carbon monoxide reaches a dangerous level # Installation is simply -- just plug it in! # Can be installed on walls or ceilings # 5 year limited Warranty