Knock Box (without holder) from RattleWare 6 x 5.5 x 4 inches
Made of heavy duty stainless steel with a welded metal bar for strong sides and replaceable rubber bar cover with an edge gasket made of molded rubber. Designed for commercial use. Replacement rubber covers can be sold separately. No holder included that also can be sold separately.
Knock box measures 6 x 5.5 x 4 inches.