This is a very rare 1940's vintage Berg Larsen Precision Slant Signature tenor mouthpiece. The original tip opening was 85, and it was opened up to .105" by Lawrie Waldron. The Precision model Berg Larsens are very rare, and have a reputation of being great players.
This mouthpiece has a similar sound to an over 2 Berg, but with a little more charecter than most Bergs we've played. The Berg also is incredibly easy to control in the altissimo, and can be pushed to really roar in the low end. These Precision Bergs are in our opinion the best Berg Larsen mouthpieces ever made, and are some of the best vintage hard rubber mouthpieces out there.