When the circuit is broken, an alarm sounds - lets you know if there's an intruder! It works independent of an expensive alarm system. Simply attach bar magnet to doorframe or window frame, aligned with the main unit that attaches to the door/window. Magnet and the main unit can be 10mm (1cm or 3/8") apart. Simple on/off switch on the side of the main unit. Main unit measures 2 1/2" x 1 1/4" x 1" and the magnet measures 2 1/4" x 3/8" x 1/2" including double-sided adhesive.

HOW IT WORKS: Simply attach the large sensor to the non-moving portion of the window or door. Attach the smaller rectangular bar magnet to the moving portion of the window or door. Turn the main device to "on" and you are set. As soon as the window or door opens, it detects that the smaller bar has moved and sounds the alarm

LOUD ALARM: The alarm is decently loud - sounding off at 100 dB, it is sure to get your attention

2 AAA BATTERIES NEEDED: Powered by two batteries that are not included but can be easily found at a local store. Easy to install in front of unit.

SIMPLE ON/OFF SWITCH: Located on the side of the main unit. Simply slide it to turn it on, i.e. when you are sleeping at night

SAFETY MATTERS: We know how much peace of mind matters and this unit will help protect you from unwanted home invasions and thefts