Knock box Grindenstein largeGrindenstein is a compact coffee knock box that bangs out your coffee grinds. Its super strong and sturdy and even tucks away on the drip tray of your espresso machine for space saving storage. Specifically designed to be stored on the espresso machine's drip tray (under the group head), Grindenstein's unique height reduces clutter on the kitchen benchtop and fits easily in the top rack of the dishwasher. Grindenstein's patented shock absorbing design