1. Door & Window Contact Sensor: This SECRUI Magnetic Door & Window Alarm will sound a 130dB volume bell when the door is opened. It can prevent your kids from sneaking around. And it is a perfect anti-theft wireless security magnetic alarm for child, home, garage, mailbox and business security.^2.4 alarm modes: It has 4 alarm modes: 1 Ordinary alarm mode (the alarm will sound 1 minute if the door is open); 2 Wireless doorbell mode (Ding dong, rings once as a welcome tone); 3 Alarm and Stop Mode (sounds loud if the door is open, and it will stop as soon as your door is closed); 4 Door close reminder mode ("Di Di"), from bottom to top, it will remind you by repeated sound until the door is closed)^3.Easy to install: This home / window alarm security kit comes with self-adhesive pads, so no tools needed, just stick the sensor and alarm on the door or window . It can also be used as a door stop alarm, swimming pool door alarm, garage door alarm or sliding door alarm^4.Automatic and Fast Switch: With an ultra-sensitive magnetic sensor, this alarm kit can quickly detect if your door or window is open. Powered by 2 AAA batteries (not included)^