The HM Series Advanced Intelligent Thermal Sensors are plug-in type fire sensors that use a single thermistor sensing circuit to provide early warning of developing fires, together with addressable communication with the fire panel. The HM-RHSE, HM-RHSE-I provides fixed 58°C and rate-of-rise (10°C / minute) temperature sensing (Class A1R). The HM-FHSE, HM-FHSE-I provides fixed 58°C temperature sensing (Class A1S).