I TOP Knock box can dispose of your used coffee grounds quickly and easily within inches of your espresso maker. You can store old coffee grounds for gardening, old coffee grounds can be a rich fertilizer option for your garden beds. Rubberized knock bar won’t dent or scratch your portafilter and helps eliminate spills, it keeps The Portafilter Safe. I TOP manufactures different kinds of coffee waste bin by different material, such as ABS, full stainless steel, aluminum alloy ect.