Glass breakage alarm 85dB This ultra-thin glass break detection system is designed to trigger an anti-theft alarm when window or door glass is broken. Simple switches on the sides of the device allow you to turn it off or change its detection sensitivity. Its slim profile is ideal for mounting on a window or door. The alarm system requires 2 CR2032 batteries (included) which have an average life of one year. The alarm system indicates when the batteries are low and you can press the "Battery Test" button at any time to check the status of the batteries. The alarm unit comes with double-sided tape (included). Just stick the alarm system on the glass of the door or window and you're done. • Ultra-thin design• Rocker switch to select detection sensitivity• Rocker switch to select on/off mode• No tools required for installation• Batteries included. 1 year battery life with normal use• Battery test button• Warning sticker visible on the outside