This is a great example of a 1950's vintage Berg Larsen Baritone mouthpiece. The mouthpiece was originally stamped 100/1 with the offset M, but was recently opened up by mouthpiece craftsman Eric Falcon to .120". These old hard rubber Berg mouthpieces for Baritone are very rare because everyone that owns one is usually hanging onto it, or using it as there main piece.
The mouthpiece has all of the features that you would expect from a hard rubber Berg of this vintage. The Duckbill beak and boat table, and the mouthpiece is super long. Berg Baritone mouthpieces of this vintage are super long, being nearly an inch longer than current production Bergs.
The sound is incredibly rich, and is really easy to control. There is a body to the sound that is really unobtainable with any other mouthpiece.