Door-window alarm Efeatures: Easily mounted by adhesive tape to window or door. Magnetic sensor switch detects entry protecting your home or office whether you are in or out. Warning door-window sticker is supplied free in package. Operated by 3 pcs 1.5vlr44 button cell (battery included in package) Operating instructions: 1. Use the doubleside 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 arrow aligning with the reference line of the main unit. 2. Test the setup by switching the systems switch to on position of the main unit and see whether the alarm can be triggered by opening the door-window.