Rattleware Metal Holder 6 by 5-1/2 by 4-Inch Knock Box Set The durable Knock Box Holder adds stability to your knock box while giving your counter a completed look. The Knock Box is made with heavy duty stainless steel, featuring a welded metal bar for strong sides. Each box has a replaceable protective rubber bar cover, and an edge gasket made of molded rubber. The Knock Box Holder is manufactured of powder coated stainless steel that matches our modular pieces, metal coffee bag display, wire bottle racks, and wire pastry baskets The attractive maple wood knock box holder complets this set adding stability to your knock box while giving your counter a finished look.