The rubber back flush disk fits all portafilters used in conjunction with E61 groups. For example: Quick Mill, Isomac, Euro 2000, Grimac, Rocket, Rancilio, and Faema. It also fits many other 58 mm portafilters. The diameter of the disk is 50 mm. The 50 mm rubber disk is what we send with each La Spaziale machine we sell. This disk drops into the single portafilter insert baskets and works well.
The stainless steel 58 mm back flush disk also fits all portafilters used in conjunction with E61 groups. The stainless steel 53 mm disk used for La Spaziale portafilters only and includes; Vivaldi II, Mini Vivaldi II, Dream, Dream T and Commercial La Spaziale Machines.