This is a Bach 5C trumpet mouthpiece. It's a well-made piece from the popular "Corp." small engraving era. The inside of the cup has a dimple-like "fosset" treatment. It seems some manufacturers once applied this to improve airflow and playing feel. There is overall plating wear from use. There are signs of repair on the shank end, and the rim has been intentionally stripped of its plating. There is also plating wear around the outer circumference of the cup from the attachment and removal of weights, etc. Although the plating wear is noticeable, it is still playable and offers the feel of a slightly deeper cup from the Corp. era. How about this for those who want to try a fosset-treated mouthpiece?