I used this mouthpiece for euphonium for about six months after purchasing it used. I am selling it because I bought another Greg Black mouthpiece. It's deeper than a 5G, so I think it would be suitable for the rich tone of a euphonium. There are some minor scratches on the shank from insertion. Please consider this item as used. There is no original box, so I will wrap it in cushioning material (bubble wrap) for shipping. 5GD: Cup Inner Diameter: 25.8mm Cup Depth: Medium Deep (deeper than 5G) Rim Width: Medium Wide