Simply fits to the roof of the garage in same way as a Smoke Alarm and provides 360 degree protection at a range of up to 20 feet. Once fitted the alarm is armed using an infared key fob and when triggered emits a 130dB siren which not only alerts the owner to the threat but also acts to disorientate the intruder. Easy to fit, no wiring required. Requires 4 x C batteries (not included). Ideal for ceiling installations.