Designed to fit 54mm Breville Portafilters and also BES870/875/878/880 portafilters Funnel attachment for the portafilter prevents messes by preventing the coffee grinds from overflowing and spilling around when grinding or tamping your brew Twist the funnel onto the portafilter and insert it into the grinding cradle After dosing your brew, you can tamp the coffee grinds while the funnel is attached to save time