Bosch D273THCS Smoke/Heat Detector 135F, Relay and Sounder

The D263/D273 Series are UL Listed, open-area detectors designed for use with commercial fire protective signaling and household fire warning systems (refer to NFPA 72). For commercial and industrial installations, space the detectors 30ft (9.2 m) apart as recommended by NFPA 72. An LED indicator flashes approximately every 3.5 sec to verify the detector has power and the smoke sampling circuitry is functioning. The LED latches ON during an alarm, allowing the user to easily verify individual detector alarms. After you clear the alarm condition, reset the detector by interrupting power.