The Key Chain Alarm combines two great deterrents against attack: a 125db alarm and a flashing light. This Key Chain Alarm attaches to a key chain for easy accessibility. Hidden disarm switch ensures that only the owner can deactivate the alarm. Can also be used as a flashlight. This ,em>Key Chain Alarm operates on 1 12v battery that is included. The unit measures in at 3" x 1 1/2" x 1/2"