The Glass Breakage Alarm is an effective low-cost vibration alarm that could be used for securing windows and doors. The glass alarm can also be used as a personal property alarm that can protect computers, TVs, stereos etc. The glass breakage alarm includes a 12 Volt battery and strong adhesive tape. Just turn the switch on the side of the unit to the on position and when the class is hit, knocked or broken by anyone or anything the siren will sound for approximately 30 seconds and then it shuts off and resets. The glass breakage alarm is 2 inches tall.