[Magnetic Wireless Sensor Alarm]: The alarm is triggered after the entrance door or window is opened. The alarm system will be activated when the door is opened more than 0.6 inches. [Super Powerful Alarm]: The 130 decibel siren can not only cause a huge shock to the thief, but also can wake you up in your sleep to prevent terrible accidents. [Easy to use and install]: Wireless remote control, easy to use. Two installation methods, stick with double-sided stickers or tie with straps, no tools required. It is suitable for entry warning systems in homes, apartments, mobile homes, offices, hotel rooms, garages and more. [KEEP YOUR CHILDREN SAFE]: This magnetic wireless sensor door and window alarm is powerful enough to detect entry, let you know when your child opens the door or window to prevent children and babies from going out, no matter you are in Inside or outside. Most importantly, if you have a swimming pool in your home, installing a door alarm is very necessary. [Don't worry about not working]: The anti-theft alarm can be used for one year without changing the batteries frequently. Beeps when the battery voltage (excluding 2 AAA batteries) drops below 2.1V. Don't worry about not working.