Universal Heavy Extreme Duty Sway Control Ball Mount (SWAYCONTROLBALL)Description Fits: Medium, Heavy, & Extreme Duty Hitches (with required Sway Control Dual Ball) The BulletProof Sway Control System helps to eliminate the sway that can happen while towing; this could be from wind, passing vehicles or uneven road surfaces. The system connects from the front of the trailer to a mounting point on the hitch and is designed to stiffen the connection between the vehicle and the trailer, keeping it straight and in line while