【ALEXANDER Mouthpiece】Horn 8M 【No. 8M】 Cup Diameter: 17.50mm Bore Diameter: 4.00mm Cup Depth: 28.00mm Rim Thickness: 4.00mm Features: For B♭ and B♭/F double horns, similar to No. 8 but with a larger bore diameter. Reduces resistance and improves the feeling of blowing. Retail Price: 16,500 yen It came with the instrument when I purchased it, but I rarely played it and it has been kept unused.