Majority of the E61 group heads made these days are very similar, then machine manufacturers will use either an 8mm or an 8.5mm group gasket.
Cafelat 8mm E61 Group Seal Gaskets Fit the following machines: All E61 Modern Replica groups such as: Isomac, ECM, ECM Germany, QuickMill, Rocket, MyWay, BFC, VBM, Brasilia B61 groups, Faema E61 group, Lever groups, E64, La Pavoni – some machines such as their E61 group, Futurmat Ariete, Wega E61 style group.
What is the difference between 8mm and 8.5mm Group Seal?
The thickness of the gasket will determine the “lock-in” position of the portafilter handle. Ideally you want the handle to lock in directly towards you (6 o’clock position). If the gasket is too thin it will lock in too far. If the gasket is too thick it will not lock in enough.