Reply to BCD3000 knobs

Hi there!

I have a question... I have a Behringer BCD3000 and I don't like the plastic knobs. I want to replace them with a rubber feel knobs. I live in Holland and there are some in a webshop here, but how do I know if they fit? Are there different fitting sizes? How do I know how much mm my behringer's knobs are?

Thanks!!