NO STOCK - BACK ORDER - 4WTRB 4-wire, photoelectric i3 smoke detector with thermal sensor and Form C relay Replacement For System Sensor 2112/24R, 2112/24TR2112/24TS Detection: Photoelectric Wiring: 4-wire Heat Sensor: 135°F (57.2°C) fixed Operating Voltage: 12/24 V non-polarized nominal, 10 min. to 35 max. ...