Bellaire Dynamic 43 Tenor Trombone Mouthpiece Brass Gold Plated Medium Cup. These mouthpieces are rare to come by. I am listing a total of three. (1) Bell-Air Rite Cup 43, gold plated, (2) Bellaire Dynamic 43 gold plated, and (3) Bellaire 41 silver plated. All of them were worked on by Ken Titmus. As is, used.