The Denis Wick Classic 5BL Trombone mouthpiece is a high-quality silver-plated mouthpiece that is ideal for principal players. This design is based on the original 4AL Mouthpiece designed by Denis Wick to reliably play higher notes. Denis Wick have a proven history of designing quality mouthpieces and are used extensively by professionals including players in the London Symphony Orchestra. The cup is of a medium depth and the rim provides a comfortable lip support. The throat and back bore provide a secure amount of resistance. This will help you to reliably achieve high notes. The medium back bore profile also helps with this by giving a little resistance balanced with great projection.