This is a set of three items: a Crampon alto saxophone mouthpiece, a Bay ligature, and a Yanagisawa plastic cap. The Crampon mouthpiece is made of hard rubber and has flat side walls, similar to a Brilhart. The tip opening is slightly narrower than my Meyer 6MM, so it's probably around a Meyer 5-6, and in my subjective opinion, it didn't feel particularly narrow when playing. The Bay ligature is a 1-screw type from the early 30-year-old model. It's in beautiful condition as I've only used it a few times since purchasing it. *No returns or exchanges, please.*