System Sensor, 12/24 V, Photo, Relay, Heat, 4-Wire, SS Model #4WTR-B.
Smoke Detector Head & Base. Conventional, 12/24 Volts, Photoelectric, 4-Wire W/Heat Sensor & Relay, No Audible. System Sensor Model #4WTR-B. These detectors have never been out of their boxes. Just Received 01-10-2025.