The DH Series Electromagnetic Fire Door Holders are constructed of the finest materials and workmanship available. Each door holder is made of durable diecastmetal and offered in a powder coated finish. Installation is easy with DH Series installation technique - an adhesive template assures alignment without secondary adjustments. No brackets are required for recessed, flush or surface mounting (the surface mounting box has three conduit ready entries). Plus, the new catch plate features two pivot points and two way adjustability to further ensure perfect alignment. Optional extension rods are also available for providing the proper gap distance between the door and wall. The basic units offer superior reliability with built-intransient protection and low residual magnetism so they release easily even on new ADA low pressure door closers.