... System Compatiable ROR, Fixed Temperature Double Alarm Modes 2Wire Conventional Heat Detector --- HM-203HC-24Wire Conventional Heat Detector --- HM-203HC-4Power Supply Non-Polar Input Low ... .5A@DC28VComply toEN-54-5, UL521, GB4716-2005DimensionΦ100 * 46mm Conventional Heat Detector (Rate-Of-Rise, Fixed Temperature)