Selected as a sub mouthpiece from over a dozen at a musical instrument store in Tokyo in October 2025. I'm selling this one because I've settled on another BD6. It seems to open slightly wider than a B40, but the blowing feel is similar to the BD series, with the air flowing through smoothly. There's no pitch instability, which is common with the BD series. Compared to the B40: The low and mid-range are very similar, but there's no feeling like it might "gag" when trying to play a strong low note. The high range also allows the air to escape well, so there's no feeling of it getting stuffy. I've been using a B40 for a long time, but due to repeated minor changes, it's become difficult to find a usable one among the recent B40s... I reluctantly tried BD4 and 5, but they didn't quite fit. If you've had a similar experience, please give this a try! ( ˊᗜˋ)(ˊᗜˋ)(ˊᗜˋ ) I recommend V12 size 3 reeds! Thank you!