Thank you for viewing. This is Willie's PJ AX. It has an inner diameter of 17.53mm, a throat diameter of 4.2mm, and a U-cup, with an Alex shank. I tried it out, but ended up going back to my usual mouthpiece, so I'm putting it up for sale. As stated on DAC's website, I think it's a mouthpiece that's easy to play for extended periods thanks to its exquisite rim shape. There is some slight blackening, but it will probably disappear with polishing.