The DS1109i Detector uses microprocessor-based sound analysis technology (SAT) to listen for the specific frequencies associated with breaking glass. It can be used to detect breakage of plate, tempered, laminated and wired glass types. A built-in environmental test feature alerts the installer of false alarm hazards in harsh environments. It is specially designed to mount on door or window frames. A built-in magnetic contact allows monitoring of a door or window opening.