heat detector, heat alarm HD-912 provide fast and reliable response for heat 57C (135F) detection, UL521 and EN54-5 approved heat detector, heat alarm with fixed and rate-of-rising temperature heat detector, heat alarm Feartures:1)2 or 4 wire modles2)Advanced detectiona and discrimination algorithms3)Easy installation and mantenance4)Sleek low-profil housing design5)Durable sensor head , no need ...