... door sensor, door detector, wireless door alarm window alarm, door alarm, entry alarm, window sensor, window detector, door sensor, door detector, wireless door ... unit at the side of the door/window and attach the bar magnet to door/window frame with the arrow aligning with ... of the main unit. This device can apply to door, window and etc. Specification:Button battery: LR44 * 3pcsSound Volume: Approx ...