Rate Of Rise Heat Detector, Model: AHR-871 Heat-sensing diaphragm can operate for unlimited number of time and is not affected by room temperature. SPECIFICATION Various Types: 2-wire, 3-wire, 4-wire Voltage range : 12 ~ 30V DC Alarm current: 40 mA (2-wire, 3-wire), 35 mA (4-wire) Ambient Temperature: 0ºC ~ +55ºC Weight: 130g Color: white