Portafilter inserts are an often overlooked item that is a key component to pulling espresso shots. This Single Portafilter Insert (02067-STDS) from Espresso Supply is a high-quality replacement insert. This insert basket is designed with a narrow base to ensure proper extraction of the coffee. This insert basket fits all 58 millimeter portafilters creating a secure fit against the espresso machine's gasket which directs the hot water through the insert and coffee. This single insert is narrower than a double insert holding less tamped espresso grounds.