The 1560 series electromagnetic door holder is designed for use with self-closing fire and smoke barrier doors. When deactivated, helps control the spread of fire and smoke by automatically releasing doors from an open position for simultaneous closing. Use independently or with any fire or smoke detector system. Fail-safe device, when electrical power fails, doors will release to close automatically. Designed to work with Sargent door closers. Recommended vertical location is on top rail of door, within 6" of lock stile edge. Fits standard outlet box.