Developed in response to requests from the Mexican Banda Music community for an HR* Clarinet mouthpiece with an even larger tip opening than the 10 model. ?Once? is the Spanish word for 11. Largest tip opening of any commercially available clarinet mouthpiece on the market. Because so many clarinetists in the Banda community play the HR* Clarinet series, it seemed only natural to name this new 11 tip opening the ?Once? in their honor. Still very easy to play. Will give you the biggest sound of your life and make playing the clarinet more comfortable since you will have as much volume as you need.