Bach Trumpet Mouthpiece 8C New, unopened. Bach Trumpet Mouthpiece Silver Plated (SP/Silver Plated Finish) Bach mouthpieces are the most widely used worldwide, from professionals to beginners. They will upgrade a mediocre instrument and make a good instrument even better. They have a rich tone, excellent intonation, respond well from high to low notes, have a rich resonance, produce consistent tone throughout the range, and have moderate resistance that prevents fatigue. Г8CJ Rim inner diameter: 16.20mm Rim thickness: Slightly wide, slightly flatter rim than a 7, with a rounded inner rim. Cup depth: M (medium) Same cup as the 7C, but the rim shape is suitable for those with protruding front teeth.