This is a Best Brass 2B mouthpiece for bass trombone. The inner rim diameter is close to a Bach 1-1/2G, and the rim edge is clear, making it feel easy to articulate. Also, the cup depth is shallow, so I think it's easy to create a bright sound that is easy to match with 1st and 2nd trombones. Personally, I felt it was suitable for long performances that require stamina, such as in wind bands and big bands. The gold plating is thin, mainly on the shank, but there are no major scratches.