Similar to Bach 6.5AL or Schilke 51. Fits all older British & European models (including Besson, Willson, some Hirschbrunner and pre-1974 Boosey & Hawkes) with "medium," "British" or "European" sized receivers. The shank on this mouthpiece is larger than traditional "small bore" and smaller than "large bore" trombone models.
• 25.4mm cup diameter • 7.12mm bore • Medium V-shaped backbore