Made by Atelier Tsubasa, original trumpet mouthpiece "3CS" with a throat of 26 and a backbore of 24. The following is a reprint of Atelier Tsubasa's description: A standard all-genre mouthpiece, based on the Bach 3C size. It was created with the aim of achieving "smooth blowing," "smooth transitions across all registers," "good responsiveness," and "maximum sound efficiency with minimal effort." ~Specifications~ ・Rim The semi-flat shape of the "MV 1-1/2C" made by Mr. Kameyama, which is loved by players around the world regardless of their professional or amateur status, has been retained, with the inner diameter adjusted to the 3C size. This shape provides both stability and control. ・Cup The depth of a modern 3C, producing a bright and brilliant tone. ・Throat #26 ・Backbore #24 (Symphonic) I believe this mouthpiece has a tone that is not the shrill sound often associated with a standard back 3C, but rather a fullness and warmth that can be used in classical music, combined with brightness. It can be used as a main mouthpiece, and it is also a good mouthpiece for those who mainly use a slightly larger mouthpiece and want to switch mouthpieces depending on the piece of music.