Super loud 90 dB alarm – This Magnetic sensor window door alarm loud enough to detect entry, prevent kids and babies going out the house, protecting your home or office whether you are in or out..Magnetic sensor switch detects your door or window. When someone opens the door or window illegally (the relative position of the primary and secondary parts changes), the alarm can issue a strong alarm, warning the intruder to leave and remind the owner..EASY INSTALLATION - Easy stick installation and operation, press on/off switch to power on/off then insert 2 PCS AAA battery (battery do not contain in the box),tear the double-sided adhesive on the back, paste the door knob alarm on your target position. (NOTICE: MAKE SURE THE GAP BETWEEN THE ALARM AND MAGNET PART WITHIN 0.6IN.).ULTRA-SLIM DESIGN - Size: 3.4" x 1.1" x 0.6, this door and window alarm with 2 adjustable settings (on/off). Perfect for home, office, garage, dorm room, apartment or even RV..WHAT YOU GET – 13 packs super environmentally suitable, stable, dustproof window door alarms, 100% customer satisfaction service, value for your money, any questions, do contact us for help! We are always here to help you out.