So I actually ordered this by mistake, I meant to order a 3C. However luck was on my side because this 7D is actually working really well. My 10 year old son is a brand new player, with a small mouth and thin lips. He was having a little trouble with the Bach 7C that came with his trumpet... Huge difference with the 7D. I don't know anything about mouthpieces and these two look exactly the same to me, but my son sounds so much better when he uses this mouthpiece.

Make sure it's what you need.he evidently doesn't take returns.