Flugelhorn mouthpieces are available for every Curry rim diameter. Two cup styles offered:

J is a convex-concave cup #19 bore (replaces FLM cup)
FL is a traditional cup #18 bore suitable for most work
FLD  is deeper with #15 bore

Universal Shank taper: fits Bach, Yamaha, and just about anything that takes a tapered shank. Fits Couesnon
Note: Older generations (pre-2022) of Curry Flugelhorn mouthpieces were marked Y, B, and F to indicate the type of shank. These shanks have been superseded by the Universal shank.