This is an Alexander 8F horn mouthpiece. There is a slight distortion in the shank. The cup is shallow, so it may be suitable for those who lack endurance, those who want to improve their high range, or for use with descant horns, etc. Please understand that this is a used item before purchasing. Below are the catalog specifications: Inner Diameter: 17.5mm Throat Diameter: 3.7mm Cup Depth: 24.0mm Rim Thickness: 4.0mm Cup: V-cup Shank: American (US)