This is a French horn mouthpiece from Willie's Custom Brass, a brass instrument maker in Yamanashi, Japan. Willie's French Horn Mouthpiece SJS standard shank. U cup, inner diameter 17.45mm. I'm selling it because I've escaped the mouthpiece rabbit hole. Since it's used, no returns or exchanges are accepted. Please refrain from price negotiations. If it doesn't sell, I will lower the price. It will be packaged and sent with bubble wrap.