Introducing the Norton Rixson 993M Electromagnetic Door Holder, designed for both surface and concealed mounting. This robust unit boasts an impressive 300 lbs holding force, ensuring your doors stay securely in place. With a total projection of 5-1/4" (133 mm), it fits seamlessly into various settings. The included switch box measures 4-1/2" x 4-9/16" x 2-1/2" (114 x 116 x 64 mm) deep, providing convenience and ease of installation. The armature plate is thru-bolted for consistent magnet contact, while the heavy-duty adjusting screw allows for precise alignment. A test switch is included, and a key switch can be used for easy release. Please note that substantial wall reinforcement is required for installation. Upgrade your door security today with the Norton Rixson 993M!