K&G Baritone 4.5B silver plated, Mouthpiece for Baritone Horn, Inner cup diameter: 25.90 mm, Cup depth: B (medium), Medium-wide rim, Small shank, Silver-plated, The design of the Kurun & Gilbert mouthpieces is based on years of research and findings in fluid dynamics and acoustics, Intonation, accuracy and sound projection are a given