The DS1100i Detector Series uses microprocessor-based sound analysis technology (SAT) to listen for the specific frequencies associated with breaking glass. The DS1101i, DS1101i-BEL, DS1101i-CHI, and DS1101i-FRA can be used to detect breakage of plate, tempered, laminated and wired glass types. A built-in environmental test feature alerts the installer to false alarm hazards in harsh environments. The round detectors mount on the ceiling or walls.