This is a trumpet mouthpiece. ■Manufacturer: Stork ■Model: 5BC (C backbore) ■Finish: Silver-plated ■Outer box: None ■Condition: Clean condition with almost no insert marks. It has a slightly deep cup. It has a slightly large C backbore. Perhaps it's a semi-symphonic model? It's a popular backbore among orchestral players for its dark yet well-defined tone. Characteristic of the Vacchiano model, the area before the throat is slightly thicker, giving it a shape similar to a double cup. I personally highly recommend Stork mouthpieces.