Designed specifically to fit the Porlex grinders and the ROK and Presso portafilters, this nifty tamper base fits right on the Porlex container bottom! At 49.7 mm outside diameter, it is the ideal size for either the standard portafilter or the naked portafilter! The Porlex ROK Tamper has a black, case hardened finish that compliments the Porlex nicely. Perfect for travel or everyday use! Porlex grinder NOT INCLUDED.