This is the Laskey 30K, which was a hot topic for a while. It's a mouthpiece developed for F tubas. I preferred the sound of the 30 over the 28, so this is the 30, which has a slightly larger bore. It's almost unused, so it's in good condition. The shank is American, as shown in the second photo. Rim inner diameter: 32.89mm Throat diameter: 8.20mm The following is quoted from Tuba Man Plus: This is a new model announced in 2023, which was not available in the original Laskey lineup. It was produced under the supervision of Chuck Kerrigan, Eastman's Artist Relations Manager and a tuba player. It has a deeper cup than the C type and is a U-cup mouthpiece that is not as C-tuba-like in sound as the F type. It is designed with a balance that reflects the current standard for F tuba mouthpieces.