The ShatterPro 3 Glassbreak Sensor listens for actual patterns of breaking glass, using Pattern Recognition Technology. Its coverage pattern can be easily adjusted and interference outside the range will not cause false alarms. These sensors detect glass breaking in a full 360 degree coverage pattern, with an adjustable 3 to 35-ft.range. A simple hand clap feature lets the user confirm that the sensor is operational, or a handheld tester can be activated at close range.