Please note that although the gaskets are strong under compression, you should never use a sharp tool like a screwdriver to install them. This may tear the silicone.
Cafelat's group gaskets are made from food grade FDA silicone. Unlike regular gaskets that are made from rubber these do not have any smell or taste whatsoever, and are easy to change since they will not bake rock hard like rubber does. If you have ever struggled to change an old gasket you cannot help but notice the awful smell and the black soot that comes off the rubber. And that is what you are potentially consuming with each drink.
Cafelat have spent months testing and adjusting the material so that these have the same compression strength as rubber, but are also softer so that it is easier to create a good seal.
Size for Nuova Simonelli 8.3mm gasket: 71mm x 56.5mm x 8.3mm (Red colour): SGS food test report
These are the newer conical shape for the Appia/Oscar/Musica If you are unsure please measure your existing gasket to check the thickness.