Depending on the valve and who made it, while a few use common parts across brands, you usually need to know not only the brand, but also the model which is why it's always a good idea to retain the installation instructions...I know, trying to keep something like that over many years doesn't happen all that often. On some, very popular valves, some aftermarket companies make replacement parts, but usually, if the OEM items are still available, they will tend to work better longer.