System Sensor 4WTA-B Photo Detector w/ Thermal Sensor and SounderThe System Sensor 4WTA B is a 4 wire, photoelectric i3 Series smoke detector with thermal sensor and built in sounder designed for use with an i3 Series compatible control panel. Heat Sensor 135F (57. 2C) fixed Sounder 85 dBA Detector is supplied with a mounting base that can be mounted: 1. To a single gang box, or 2. To a 3 12 inch or 4 inch octagonal box, or 3. To a 4 inch square box with a plaster ring, or 4. Direct mount or to ceiling using