The Bach Trumpet Mouthpiece in Silver has been the standard since being created by trumpet master Vincent Bach. This series of Bach trumpet mouthpiece is available in a variety of sizes to meet the needs of the individual player. The Bach mouthpiece numbering system is arranged in an orderly progression from the largest to smallest diameters numbered from low to high.   7C- Probably the most widely used model in the world. Its brilliant tone is preferred by school musicians and by artists. 16.20mm cup diameter. Rim: Medium wide, lowered toward the outside. Medium sharp inside. Well rounded edge with a perfect grip.