Overhead Door Holder 280 Sensaguard
Glynn-Johnson provides a holder/release smoke detector designed
to allow fire doors to remain open for easy passage, while releasing
doors in an emergency. The SensaGuard™ Series 280 features an
internal ionization-type smoke detector, powered by a single
nine-volt battery. Its fail-safe operation automatically releases
the door when battery power drops below 7.2 volts.
Uses a household 9 volt battery.