Stainless Steel 7" Flat Shank with Cyprium Ported Barrel (MB 33) Copper Inlay Mouth. This mouthpiece is made of Cyprium, a nickel-free copper alloy that encourages salivation. About the mouthpiece: the 33 is the mildest Myler mouthpiece in terms of tongue pressure. The generously wide port allows room for the tongue to pass under the bit and swallow. Because this mouthpiece does not rotate on to the tongue and the port is wide, it applies little to no tongue pressure, working primarily off the bars, lips, chin and poll. The port on this mouthpiece is only 1 ½" high, so it will apply little to no palate pressure. Because the 33 offers such a high degree of tongue relief, the horse that goes well in this mouthpiece has a trustworthy and consistent disposition, trained to work off the leg and seat as well as the hands. This mouthpiece has Independent Side Movement . For a slight increase in tongue pressure, see the 43LP. For same tongue relief without Independent Side Movement, see the 16 (Western) or 15 (English). For the same tongue relief and Independent Side Movement, but with a slight degree of collapse, see the 05. From The Level Best for Your Horse by Dale, Ron and Bob Myler. ©Toklat Originals, Inc.