M15 mouthpiece for Bb clarinet that was designed by Robert Van Doren and provides time proven standard for musicians worldwide. It is easy to articulate and provides a colourful spectrum of sound. With its long facing, Profile 88 beak and tip opening of 103.5 (1/100mm), it provides an impeccable intonation, crisp and accurate articulation, and unrivalled response. This mouthpiece works best with Vandoren #3.5 to #5 reeds.