the Dee-ring, as its name suggest, has a ring shape like a "D" with the straight part of the "D" attached to the mouthpiece of the bit. The straight bars of the Dee-ring provide a lateral guiding effect. This is because the bit ring is pulled against the side of the mouth opposite the rein that is activated, pushing the sides of the D against the horse's jaw, helping to turn him. The Dee-ring is especially fixed in the horse's mouth, because its shape does not allow the bit to rotate. The Dee-ring is most similar to the full-cheek. The Dee-ring is the traditional bit used in hunt seat riding, and is the most common in that discipline. It is also popular in horse racing. The Dee-ring is not as popular in dressage, nor is it seen much in eventing or show jumping.