The Coronet Copper and Steel Roller Dee Snaffle Bit. The Dee ring compromises between an eggbutt and a full cheek snaffle, preventing pinching at the corners of the mouth and without the dangers posed by the arms of a full cheek snaffle. The copper rollers help to encourage salivation and prevent the horse from taking hold of the bit. The single joint creates a nutcracker action which puts pressure on the tongue, the roof of the mouth and the bars of the mouth