Door Alarm, Wireless Door Window Contact Sensor For Kids Safety Door Window Contact Sensor: This door window chime alarm sensor will emit loud volume alarm of 70dB when the door is suddenly open. It can prevent your kids from sneaking out. And its a perfect wireless security magnetic alarm for kids safety, anti-theft, home, garage, postbox, and business security. Easy to Install: This home/window contact sensor alarm security kit come with self adhesive pads so no tools are required, just had to stick the door alarm sensor on the door or window. It can also be used as a doorstop alarm, pool door alarm, garage door alarm or sliding door alarm. Fast Automatic Switch: With ultra-sensitive magnetic sensor desgin, this contact sensor kit can quickly detect your door or windows status. Its powered by 2*AAA battery (Not included). color: White Size: 3.1*1.9*9.1cm Quantity delivered: 4 pieces