YAMAHA Yamaha Trumpet Mouthpiece 11C4 This is a Yamaha trumpet mouthpiece, a standard brand for trumpets. The size is 11C4, a size that can be used for all-around playing. It's roughly equivalent to a Bach 7C. It's a very versatile mouthpiece, and personally, I think it's easier to blow through than a Bach. There are some scratches from use, but there are no scratches or dents that would interfere with playing.