This knock box is used to collect used espresso grounds from your machine's portafilter, or filter basket. Its stainless steel, rubber-wrapped knock bar provides the perfect surface for "knocking out" spent coffee, eliminating multiple trips to the garbage can or sink for disposal. This box comes in a standard pan size, which allows it to be set into or placed on a countertop for storage. Best of all, the bar is removable for easy cleaning or replacement (sold separately) as needed. Only Choice replacement bars are compatible with this box.