I'm refurbishing an Angram beer engine and I need to replace the seals for the cylinder. The only problem is that I can't find out where to buy them or what they're actually called. I talked to the guy at UK brewing and he was great, but he said that they'd be out of stock for probably a month or so. Also, it seems like these sorts of things should be easy (and probably cheaper) to find via McMaster or someplace similar, but I don't know what to search for. Clearly, they're not O-rings but the correct name eludes me. Anyway, here's a picture. You can see why I want to swap them out If any of you guys have suggestions on what these are called and where/how I can find a few, I'd definitely appreciate it.