Superior Brass Door Horse Knocker 3037 Door Knocker allows those outside a house, or other building, to make themselves known to those inside. Door Knocker Function - fastened to the door by a hinge and can be raised to make noise by striking a plate that is installed on the door or the door itself. Features: Easy to install Perfect decorative accent for a front entryway Enables guests to notify you when they arrive Specifications: Size: 125mm Finish: Polished Brass