Corkscrew Mouth The Full cheek, has simple action on the lips. The main feature of the full cheek is to help steering by giving lateral control. This bit helps the young horse not used to aids or the adult horse presenting lack of flexibility. This bit has 1 1/2 ring and 10 mm mouth. All our Bits are High Quality German or Stainless Steel made by Coronet or Korsteel Size: 4 1/2, 4 3/4.