French Horn Yamaha Mouthpiece Model 32C4 - Model: 32C4 - Inner Diameter: 17.5mm - Throat: 3.98mm This is one of the popular standard models. It was used for about a month, and I am selling it because the shank didn't fit. This mouthpiece has no manufacturing variations like overseas products, and you can feel the stable quality of Yamaha. It's a standard type that works well from top to bottom.