Height: 86 mm Width: 86 mm Projection: 52 mm features: Electro-magnetic door holder surface mounted fitting Made to suit standard electrical backbox Supplied with on/off switch Designed to hold fire doors open and release them automatically in the event of a fire, when installed as an integral part of any fire alarm system Keeper plate supplied is self aligning in any direction 24 Volt D.C fail safe wall mounted Floor mounting bracket available to order The unit is housed in a BS.5733:1995 pressed steel box Tested to:EN1155 Resistance: 330 Ohms Power: 1.75 Watts Holding force: 155N