Stainless Steel 3 3/4" Dee with Stainless Steel Mullen Barrel Low Port (MB 06) Copper Inlay Mouth. About the mouthpiece: the 06 mouthpiece is a Myler alternative to the traditional mullen mouthpiece. Like the traditional mullen the 06 is also a solid curved bar that sits across the bars of the horse's mouth, but it has a wide low port that allows the tongue to pass under the bit comfortably. The port is ¼" high, just enough to allow the tongue to elevate slightly and swallow, but not high enough for palate pressure. Because the port is low, the 06 doesn’t offer as much tongue relief as other Level Two-Tree mouthpieces with slightly higher ports because the tongue is still somewhat restricted. The curved mouthpiece wraps the horse’s mouth, allowing more space for the tongue under the bit. When the reins are engaged, the 06 applies pressure primarily to the bars and lip. This mouthpiece also has Independent Side Movement . This mouthpiece is a step up in tongue relief from Level Two. The 36 mouth piece offers more tongue relief when the reins are relaxed, but more tongue pressure when the reins are engaged. For more tongue relief, see the 43LP. From The Level Best for Your Horse by Dale, Ron and Bob Myler. ©Toklat Originals, Inc.