Thank you for viewing. This is a Stork CMA15 horn mouthpiece. Specs: CMA15 Inner diameter: 17.5mm Cup: medium deep Bore: 4.6mm Retail price: 15,400 yen I use a Paxman M20 and am selling this because I will be using the CA15, which is one step deeper. This is a versatile mouthpiece among the custom models, with a comfortable feel and is easy to play. Thank you.