As title, hope e4 calliper in blue. I was going to send my brakes off to hope for a refurb as the pistons are stuck in the e4, but it's also got some scuffs so on the lookout for a better one before I send them off.
I don't have one spare but from memory the E4's are pretty easy to self service? I've certainly freed up mine in the past with a little help from Google.