3-Piece with Copper Roller Snaffle. Dee Ring. The Dee ring applies pressure to the horse's cheek on the opposite side of the face from the rein you pull to allow for better flexion. Mouthpiece breaks over the bars at an angle to contact new nerves and add some tongue pressure for better control. Copper adds a sweet and sour taste for moisture and will also act as a pacifier for horses that chew on the bit. Copper is a soft metal, watch for excessive wear.