The elliptical joint is an oval shaped link in the center of the mouthpiece, which is movable and rolls around the stainless steel center. The two joints allow the pressure of the bit is distributed over both the tongue and bars of the mouth and it shouldnt cause any interference with the roof of the mouth. The link uses tongue pressure to encourage the horse to go on the bit and lower the head. The brass material stimulates salivation which in turn encourages a softer mouth.