The beauties are exactly what's required - made by Bialetti, the Italian king of stovetop coffee, and built to last. These are worn out over time, particularly by those who vigorously clean their stovetops, and as they wear they reduce the function of your brewer and the taste of your coffee. If you're thinking "What filter? What gasket?" then you definitely need a new one. The 3 Cup model is made to fit a Bialetti 3 Cup Moka Express / 2 or 3 Cup Brikka. The filter measures 58mm (diameter) / 66mm (including gasket.) The 6 Cup is made for a Bialetti 6 Cup Moka Express. The filter measures 64mm (diameter) / 72mm (including gasket.) These parts are not sold separately.