【BEST BRASS JAPAN 3C】 This mouthpiece is designed to be lightweight to embody Best Brass's image of a "wonderful horn sound." Its main features are a rich resonance and a smooth, velvety feel when playing. Specifications: Rim Inner Diameter: 17.8mm Cup Depth: Medium Throat Diameter: #16 (4.50) Backbore: HR-ML This model has a slightly larger rim inner diameter than the HR-5C. The other specifications are the same as the HR-5C, resulting in a rich sound, making it suitable for large orchestra players. It is also easy to play in the low register. Can be used with both large and small bell horns. Comparable to: Bach 3 (slightly larger) There are some scratches and dirt overall, but there are no problems with use. Also, while BEST BRASS mouthpieces are usually gold-plated, this one appears to be silver-plated.