Sonic Entry Wireless Audible Door and Window Alarms (4 Pack) Protect your home doors, windows and cabinets. Alerts you if an intruder enters your home. Great for monitoring door activity with children. Has two audible settings- 90dB Alarm and Chime sounds. Wireless design- no tools needed and installs in minutes. Features and includes: 4 x Sonic Enrty window/door alarms Alarm and chime modes Self adhesive backing No tools needed Works on almost any window Great for monitoring children Each alarm module requires 3 x LR44 button batteries - included