Bach 350 Trombone 7C

I got this Bach 7C small shrank mouthipiece and now, after few weeks playing with it, I can say it's a great option. Previously I used a 12C, but this one give me the chance to play louder and more confortable in both high and low registers. The only issue, as sometimes happens with Bach mouthpieces, is that they are a bit hard on the lips, a bit "stinging".