Features The Bach 5G Small Shank Trombone/Euphonium Mouthpiece is made for players with good, natural embouchures. It features a rather large cup, and helps produce a full, mellow, sonorous tone. Also has the .276” throat and #429 backbore compared to the 5 Mouthpiece Cup Depth: Deep Approximate Cup Diameter: 25.50 mm Rim Shape: Medium Wide, Semi-Flat Model:3505G Manufacturer:Bach