BestBrass 5C French Horn Mouthpiece. BestBrass mouthpieces are usually gold-plated, but this one is silver-plated. I purchased it used and tried it a few times. There are minor scratches from normal use, but there are no major scratches or dents, and I think the condition is good. Rim Inner Diameter: 17.5mm Cup Depth: Medium Throat Diameter: 4.5mm Equivalent to other brands: Bach 7, slightly smaller --- It features a rich sound and a playing feel with a velvety smoothness. The inner diameter shape and beautiful exterior design, based on precise design, achieve a wonderful resonance balance. It can be used with both large and small bell horns. New price: 23,100 yen