The Balldog slips over your trailer ball using a pear link to establish a convenient anchor point for pulling or towing. Balldog can also fit into a receiver tube using the oblong link and locking pin. This is great for securing chain, tow ropes, wire rope, etc. Twist Lock hook prevents accidental release of chain from hook and the Working Load Limit (WLL) is 4,700 lbs. Fits over 1-7/8', 2' and 2-5/16' trailer balls and into 2' and 2-1/2' receiver tubes. Patented. Balldog Plus