BACH Trumpet Mouthpiece Symphonic 3C 26 24 This is a trumpet mouthpiece from VINCENT BACH, a standard trumpet manufacturer. The size is 3C, with a throat of 26 and a backbore of 24, making it a Symphonic model. Compared to the standard 27 throat (3.66mm), the 26 throat (3.73mm) is slightly wider, and the backbore is 24 (Symphonic) instead of the standard 10. Therefore, the airflow is thicker than a standard 3C, and the sound quality has a slightly darker impression. However, it is a mouthpiece that still brings out the good qualities of a 3C, so I think it's a size that can produce sound from the low to high registers. There are some minor shank scratches, but it is in excellent condition with almost no damage.