Made by ESM, a manufacturer known for its high processing accuracy. Like the Green Line by Crampon, this mouthpiece is made by solidifying grenadilla powder. It responds well, has many overtones, and produces a very refined tone. Those who like the playing feel of Green Line clarinets or barrels will likely enjoy this. Tip opening: 1.18mm Facing: 16.5mm Since the facing measurement method seems to differ depending on the manufacturer, it is recommended for those who play Vandoren B40 Lyre, M30 Lyre, etc. I kept it in my instrument case as a spare because it doesn't discolor the instrument's keys. There are faint marks from the mouthpiece patch. Case included.