Noisy: 120 DB Siren alarm not only caused a huge shock to thieves, but also allows you to wake up during your sleep. Prevent a horrible accident. Keep your children safe and know when they open the doors! Perfect for your home, office, garage, dorm room, or even RV. Easy installation: no wiring required! No screws needed! Double-sided tape included! 3xLR44 batteries,Batteries not included.Additional level of security: ultra sensitive too Low battery indicator to check battery life. Low Battery Warning Flashing light reminds you to replace the battery to better protect your home.Easy to Use: Ultra-Slim Design unique door and window alarm with 2 adjustable settings (off/alarm). Magnetic sensor triggered alarm: alarm triggered after the front door or window is opened. Save hundreds of alarm installation costs. This is the affordable affordable price for your home. Note: The data are all measured manually, please allow 1-3cm error, due to the difference in light and display, there will be some difference. certain color difference, the actual object received shall prevail.