Open bottom knock chutes allow for under counter grounds disposal. All knock chutes are made from heavy duty stainless steel featuring a welded metal bar for strong sides. Each knock chute has a replaceable rubber bar cover and an edge gasket made of molded rubber. Knock chutes are designed for commercial use. Replacement rubber bar covers sold separately (item #25950) Knock Chute cut out dimension is 6.25" across (the gasket adds .5" of length). This is the interior dimension. We recommend that you receive the product and measure before cutting your counter.