In terms of tongue pressure, the MB 33 is the mildest Myler mouthpiece. The generously wide port allows room for the tongue to pass almost completely under the bit. It also applies little to no tongue pressure, working primarily off the lips and bars. This is because it does not rotate on to the tongue and the port is wide. The port on this mouthpiece being only 1 ½” means it will apply little to no palate pressure. It is available in two standard sizes, which are 5″ and 5.5″.