Gist BitLogic System 6" Shank Correction Bit, 5" Copper Inlaid Mouthpiece. The 6" cheek has a 2-1/2" purchase and a 3-1/2" shank. This ratio (the difference in the length of the purchase and shank) and the swept back design of the shank make this bit a mild cheek. Contact with the horse's mouth comes slowly in the form of soft pressure to all points of contact. The main point of contact is the corners of the mouth, which is a familiar spot from the O Ring. This bit may also be used with a training fork or martingale to encourage collection and poll control. The mouthpiece is inlaid with copper to stimulate salivation. The mouthpiece is 5-1/8" wide, 3/8" in diameter, and curved to shape to the corner of the mouth for soft, evenly distributed pressure to the bars, tongue, and corners of the mouth.