Foto4easy Home Security Wedge Door Stop Alarm System Device Intruder Alert Detection This Door Wedge can be easily applied to closed doors, when the door is opened it will activate an alarm alerting you of a possible security breach. Extra Loud Alarm - Sounds a loud 120 dB siren when protected door is opened Dual Function: Alarm & Door Stop Wedge shaped door stop design prevents further entry the harder they push. Bottom of door alarm has anti-slide pads to hold it secure