Gold-plated trombone mouthpiece, BM series, large shank, SP model, silver finish, providing high-quality tone. - Model Name: BM Series Large Shank SP (Silver Finish) - Material: Gold-plated - Design Features: Trombone mouthpiece Thank you for viewing. I used this a little on my tenor bass trombone. It's been tuned. It was easy to play both low and high notes. I was told that it might be better for bass trombone players to use it on a bass trombone, so I haven't used it much, but I decided to put it up for sale. Thanks to this, I can now play low and high notes with other mouthpieces as well.