Check the listing for details. CURT 21801 HITCH ACCESSORIES. Condition: New. Listed at 21.74 USD. 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. With the right accessories, the difference is a little like cruising the Grand Canyon in a deluxe RV as opposed to camping out in grandma's backyard. For protecting your trailer ball when not in use, the Curt rubber trailer ball cover is a perfect fit. This cover is designed to fit a 1-7/8 Inch or 2 Inch diameter trailer ball. You never know what obstacles the road before you might bring. The key to overcoming them is to be prepared.