Honeywell 2WT-B, 2-Wire Smoke Detector with Fixed Heat Sensor

Dimensions: 5.3 inches (127 mm) diameter; 2.0 inches (51 mm) heightOperating Temperature Range: 32°F to 120°F (0°C to 49°C)Operating Voltage: Nominal: 12/24V non-polarized | Minimum: 8.5V | Maximum: 35VMaximum Ripple Voltage: 30% peak to peak of applied voltageStandby Current: 2-wire: 50 µA maximum average; 4-wire: 50 µA maximum averageMaximum Alarm Current: 2-wire: 130 mA limited by control panel; 4-wire: 20 mA @12 V, 23 mA @ 24 VPeak Standby Current: 2-wire: 100 µA; 4-wire: n/aAlarm Contact Ratings: 2-wire: n/a; 4-wire: 0.5 A @ 30 V AC/DCWeight: 6.3 oz (178 g)Thermal Sensor: 135°F (57.2°C) fixedSensitivity: 2.5%/ft nominalInput Terminals: 14 to 22 AWGMounting: 3½-inch octagonal back box | 4-inch octagonal back box | Single-gang back box | 4-inch square back box with a plaster ring | Direct mount to ceiling