1/2PCS Door Alarm Sensor Wireless Burglary Remote Control Door Window Alarms Suitable For Home Hotel Features [MAGNETIC WIRELESS SENSOR ALARM]: Alarm triggered after the entrance door or window opening. The alarm system will be activated when the door opens more than 1cm [SUPER STRONG ALARM]: 130 dB Alarm siren can not only cause a huge shock on thieves, but also allows you to wake up during your sleep to prevent a horrible accident. [EASY TO USE AND INSTALL]: Wireless remote control, easy to use. Two methods of installation, stick with a double-sided sticker or tie it with a strap, no tools required. It is suitable for homes, apartments, mobile homes, offices, hotel rooms, garages and more entry warning systems. [KEEP YOUR CHILDREN SAFE]: This magnetic wireless sensor door and window alarm is powerful enough to detect entrances, lets you know when your children are opening doors or windows to prevent children and babies from go out, whether you are inside or outside the house. Above all, if you have a pool at home, it is very necessary to install a door alarm. [DO NOT WORRY TO DO NOT WORK]: The anti-theft alarm can be used for one year without changing the battery frequently. When the battery voltage is below 2.1V, a beep sounds. Do not worry about not working. Specifications Door magnetic standby time: about one year Remote control standby time: about one year Door sensor battery:1.5V*2 pcs (not included) Package Include:1/2PCS*Door Alarm Note: Due to different personal measurement methods, there will be an error of 2-4 cm, please understand Thanks for your support