Rattleware 6 by 5-1/2 by 6 Inch Knock Box
This knock box is made from heavy duty stainless steel featuring a welded metal bar for durability.  It has a replaceable rubber bar cover and an edge gasket made of molded rubber.  This knock box is designed for commercial use.  Replacement rubber bar covers are sold separately.   Knock box measures 9" x 5.5" x 4".