Sell DOORS AND WINDOWS ENTRY ALARM best price

door entry alarm,window entry alarm,alarm system Size: About 6.2*3*2cm,5.4*1.3*1.1cm Weight: About 40g Battery: 3*1.5V LR44(include). Instructions: 1.Use the double-side adhesive tape to fix the main unit at the side of the door/window.Attach the bar magnet to door frame/window frame with the refernce line of main unit. 2.Test the setup by swithing the system's swithing to "ON" positon of main unit and see whether the alarm can be triggered by opening the door/window.