Thank you for viewing. This is a BEST BRASS horn mouthpiece. It has an inner diameter of 17.8mm, a throat of 4.7mm, and a slightly deep cup. It's an American shank and gold-plated. I used this in high school, so there are some scratches on the shank, but I don't see any dents. Because the storage environment wasn't ideal, there are stains that won't come off even when wiped. If you don't mind the appearance, please consider it.