Glass break Detectors detect the sounds of breaking glass for home security purposes. Honeywell manufactures a Glass break Simulator/Tester (FG701) that is useful for testing the range and function of glass break sensors.
Devicebook offers a variety of Glass Break detectors with varying form factors. In general, glass break detectors should be installed on a wall or ceiling within fifteen feet of the window to be protected, with the microphone of the detector facing directly at the window. See each device's operating instructions manual for more information.