Willie's NASOTA 565 2023α Purchased about a year and a half ago and used for about a year. Personally, the rim feels smoother than the NASOTA 565, and it feels like it fits my lips better. Here are the specifications and explanation: The name NASOTA is derived from the title of the euphonium sonata composed by signature artist Hidetaka Arai himself. His works evoke a variety of scenes, such as the colorfulness of crayons, the joy of overturning a toy box, and nostalgic childhood landscapes. And the NASOTA mouthpiece was born to maximize the appeal of such works. With an extremely flat yet non-sharp edge rim and a solistic tone, this mouthpiece is finished to breathe new life into the euphonium. The "NASOTA 565 α" using the material-tempered "α material" has a richer resonance, a mellow sound onset, and limit characteristics that prevent cracking even at fff. Rim inner diameter: 25.65 Throat diameter: 7.22 Please feel free to comment if you have any questions about the price or other comments.