This is a crystal mouthpiece with a very large tip opening, yet it feels less open and low notes are stuffy, unresponsive. Bending notes is more difficult than what I hoped for. There is lots of resistance. The sound is great in the upper chalumeau and clarino registers but not very good below and above that. Nevertheless, it is a well-made mouthpice. One also should remember, it is a handmade mouthpiece and maybe other pieces are better.
Additional comment: with an extremely soft reed, the response is much better but controlling the intonation got much more difficult. And the upper register is risky and wobbly. However, the flexibility of the chalumeau and clarino registers is amazing.