Independent Door alarm sensor on the window with high db sound

Door alarm sensor magnets1.wireless door alarm
2.distance triggered sensor
3.low price magnetic sensorThis alarm work with two device, one is main device with alarm and the another is the magnetic piece. If the device is armed the device can’t be separate from each other. If not the main device will alert.Use double sided tape to fix main unit at the side of the door/window and attach the bar magnet to door/window frame with the arrow aligning with the refference line of the main unit.It will give off big sound to scare away the intruders whentwo parts are departed from 1.5cm. it often installed inthe door and window.Specification:Button battery: LR44? * 3pcsSound Volume: Approx 90db/m