This is a Vandoren BD4 HD series mouthpiece. It's for B♭ clarinet. Purchased in February 2025, it's practically unused, only tried out briefly. It feels like it resonates better than the standard BD. It doesn't seem to lower the pitch as much as the BD5. Would you like to try it? - Model Name: HD Black Diamond Clarinet Mouthpiece - Brand: Vandoren - Included: Mouthpiece pouch - Material: High-density resin #clarinet #mouthpiece