This loose ring has the Butterfly mouthpiece. The butterfly mouthpiece by virtue of its design allows a step up in control over flexible rubber mouthpieces.  This is due to to the wings and a flat port putting pressure on the tongue.

The ports for the rings are angled in such a way that that flat port lays smoothly against the tongue.  The mouthpiece is directional, so proper care must be taken that it is facing the correct way.

Made in Germany