The Dee Ring is very similar in action to the Eggbutt, it will prevent pinching of the lips and gives a slightly more solid feel against the side of the face. It also prevents the bit being pulled through the mouth. The release is slower and some slight poll pressure is introduced.
The Elliptical is stronger than the Control Plate due to it concentrating pressure onto a smaller surface area. This bit will suit a horse that pushes the bit with its tongue. The horse will draw its head back and tuck its chin in, finding a better balance of control.