B. Tilz KS Model 775D Bass Trombone Mouthpiece [Retail Price: ¥26,400] (Reference) Inner Rim Diameter: 27.75mm Throat Diameter: 8.0mm Cup Depth: Deep ● There is some plating flaking inside the cup, and the condition is not good. (The cup area that touches the mouth is fine, so it doesn't affect playing, but the internal plating flaking might have some slight impact.) However, how about it for those who want to try it out anyway? ● Because of its weight and deep cup, it has a very warm sound, which is its charm. The inner diameter isn't too large, so you won't feel like you're running out of breath, and high notes don't waver much. I felt it was a good mouthpiece. I've changed my main instrument, and I haven't used it for a while due to the tonal feel with my current section, so I've decided to sell it.