Trailer Ball Cover (Fits 1-7/8" or 2" Balls, Black Rubber, Packaged) With any towing setup, there is always the need for a few additional items. Though your trailer hitch and ball mount may be tough enough to haul that heavy load, they cannot properly tow without a few supporting players. Towing accessories are a practical addition to your rig that add the finishing touches and take your towing experience to a whole new level. The rubber trailer ball cover is a perfect fit. This cover is designed to fit a 1-7/8" or 2" diameter trailer ball (trailer ball and ball mount not included).