BOSCH ISC-FPB1-W120QS Quad Beams Indoor/Outdoor photoelectric detector, 240m indoors, 120m outdoors
The Detector Series consists of the DS453Q and DS455Q Detectors with separate transmitters and receivers. The transmitter emits an invisible infrared beam to the receiver. If the beam is broken, the receiver signals an alarm.
The DS453Q and DS455Q use four pulsed infrared beams that are designed to activate an alarm only when all four beams are simultaneously blocked. The DS453Q and DS455Q also feature interlocked upper and lower beams, signal voltage LED, and selectable environmental discrimination circuitry.