The Kidde KN-COB-B is battery operated for direct current which means that there is no interruption of monitoring due to a power outage. It also includes two LED lights; one for proof of operation, and one for the alarm.
Power Source: 3 AA batteries (included)
Audio Alarm: 85 dB at 10 ft
Size: 4 1/2″L x 2 3/4″H x 1 1/2″D
Weight: 8 oz
Warranty: 5-year limited