The Full Cheek cheek piece, will have the same effect as the traditional Eggbutt in so much as, it will prevent pinching on the sides of the mouth, however the extended pins above and below the bit, firstly prevent the bit being pulled through the mouth and secondly have the effect of guiding the horses head which is great for schooling and training purposes.
A horse shaking its head when bit pressure is applied or its tongue trying to escape the bit are classic signs the horse has a sensitive tongue. With this in mind the McHardy was created, it has a medium port creating space for the tongue relieving pressure. The Buster Roller in the middle increases bar pressure and as a result lifting the horse's head and giving more control.