The Sentronic® 7800 Series magnet releases when the fire alarm panel enters an alarm condition and the electrical current is interrupted, allowing the door to perform manually until power returns. A manual door closer is used to control and close the door. The tri-voltage design provides 35 pounds of holding force. The magnet is fail-safe and will hold the door until the current is interrupted. The SEM 7840 is low-profile recessed wall-mounted.