【Easy to use 】 Magnetic sensor switch detects your door or window. Easy stick installation and operation. It only takes 3 steps：1. insert 2 PCS AAA battery (battery do not contain in the box), 2. tear the double-sided adhesive on the backpack, paste the door knob alarm on your target position， 3. press on/off switch to power on/off. Note: When the distance between the doorbell and the magnetic sensor is greater than 0.59 inches, the doorbell will emit a sound of 90 decibels or more, to alert you or drive away thieves and protect your children | 【Suitable for Various Scenarios】Can be easily mounted using adhesive. Suitable for installation on windows and doors, providing an ideal entry warning for homes, apartments, mobile homes, offices, hotel rooms, garages, and more! | 【Extremely Loud 90 dB Alarm】 If anyone unlawfully opens a window or door (pertaining to the interchanging primary and secondary components), the alarm can emit a loud warning, urging the intruder to exit and reminding the owner. It also serves to prevent children or infants from wandering outside, securing your residence or workplace regardless of your absence. | 【High quality】Super suitability and stability. 100% New and high quality. Super environmentally suitable, stable, dust proof window door alarms | 【What you will get】 -- 10 packs window door alarms. You can use this alarm to protect children and pets, prevent theft, and remind yourself to close the door according to your needs. Its 90dB alarm sound is loud enough to focus on family safety concerns or the arrival of visitors.