A set of heavy and light cup mouthpieces for F tuba made by WHF. The rim is JW6, the cup is S6 (heavy & light), and the shaft is W6. The No. 6 model has an inner diameter of 32.0mm. I purchased these after trying them out, but I don't think I'll be using them in the future, so I'm putting them up for sale. There are no noticeable scratches or dents. Since there are both heavy and light cups, I think you can express a variety of tones. My impression is that they are not as heavy as they look, and they respond quickly, producing a uniform sound across the entire range.