5" shank mouthpiece is 5 1/2
The MM mouthpiece is designed so that when a horse is pushing on the bit the mouthpiece’s sculpted surfaces are constructed to apply more specific pressure. Alternatively, when a horse is not pushing on the bit, the smooth surfaces are more accommodating and allow the horse to run more free and aggress. The innovative contours also allow the horse, with minimal give to release and go back to the smooth, accommodating surface. There is simply put, nothing else like it in the industry today.
With the port in this bit it helps to lay the tongue flat. Some horses roll their tongue back which can cause them to raise their head and decrease the ability to breathe correctly.