If you want to dispose of the coffee grounds after preparing your fragrant favorite hot drink, you don't want to awkwardly walk with the hot portafilter to the trash can. Simply place the knock box space-saving next to your portafilter coffee machine and gently tap the coffee grounds against the rubberized bar directly from the portafilter. The high volume of the drip box is just as practical as the non-slip rubber ring on the bottom.