Ultimate Brass Bass Trombone Mouthpiece G375 Gold Plated GP ◆ Rim Inner Diameter: 28.07mm ◆ Throat Diameter: 8.26mm ◆ Cup Depth: Medium ★ Purchased as a used item, tried out a few times. ★ Original gold-plated product Although there are fine signs of use on the surface, the gold plating is in a beautiful condition for a used item. With a size similar to other companies' 1-3/8G, and a wide throat setting, it allows for easy airflow and a bright sound. Suitable for switching between tenor trombones. Ultimate Brass is a manufacturer that produces products in the United States. Founded in 2013 by SUN He, bass trombone player of the Oakland Symphony Orchestra. Unlike other brands, they do not use numbering based on size, but rather name their products based on their respective purposes and images.