This came with a violin e string that I just bought. I'm guessing it's a bridge protector, but it's already has one on it. What is this? : r/whatisthisthing
Kaplan Non-Whistling E string – Gig Violins
Kaplan KS311W Non Whistling E String – Musikhaus Thomann
4strings news and information - Choosing the right E string: what are the differences? - 4strings