... ) detection, UL521 and EN54-5 approved heat detector, heat alarm with fixed and rate-of-rising temperature heat detector, heat alarm Features:1)2 or 4 ... :57°C (135°F)Ceiling Spacing:50 foot rating for heat sensorReset Voltage:less than 1 voltAlarm Indicator:LED continuously emitting ... ) x 46mm (ht) with baseWeight:120g/set with base thermal Heat detector with UL,EN,CE,Rosh