Overview LF's espresso gasket for E61 groups is made from non-toxic, food grade FDA silicone. This makes it better than rubber gaskets since silicone doesn't have any smell or taste and is easy to change in & out. The group gasket manufacturer spent months testing the espresso maker gasket so it can both retain the strength of a rubber gasket, and also create a good seal effortlessly. *When replacing gaskets, remember the flat side lays face down. Both the 8mm and 8.5mm will work on the E61 group machines. It is your own preference as to which thickness you prefer. The thicker the gasket, the tighter the seal with the portafilter. When installing a new group gasket it will take a little time to wear it down so your portafilter once again aligns to the 6 o'clock position. Machine Compatibility Izzo Duetto IV Duetto Evo Vivi PID Quick Mill Alexia Carola Anita Andreja Premium QM67 Vetrano 2B Rocket Espresso Appartmento R58 Cinquantotto Mozzafiato - both models Giotto - both models Boxer R9 Isomac, Expobar and ECM (as long as they have an E61 group), are also compatible with this product.