you can buy the stainless steel circlips, just buy a slightly smaller size than the ones fitted. I think the recommended size (by me) is inside @Eiffel FAQ, there are also phosphated and spring steel options.
The circlips I think the Italians like to use are too large, because they follow the dimension of the slot for the circlip. The slot for the circlip has a diameter of 52mm and a groove size of 2.2mm (to allow for the shower screen thickness.
I believe they choose an inner circlip to fit this specific dimension. In something like an engine bore this could be correct because of the temperatures and pressure involved. In the group, it simply has to hold in a shower screen under no force and weighing less than 2g. It’s probably why the stainless ones break.
Below is a circlip that will definitely fit, but may still be a little tight. @Systemic bought some but I am not sure of the size.
The next size down with a bore of 48mm may just fit OK, but a circlip for a bore of 49 would be best. Unfortunately not many manufacturers make the 49mm size.
48mm also brings you down to 1.75mm thickness, which will be easier to fit in the groove which is 2.2 mm wide.
This is part of the drawing for the group with the circlip groove indicated
P.S. You can’t trust anything from china, circlip wise…you don’t know what you will get.
