Reese Towpower 7063300 5" Drop Class V Interlock Ball Mount Interlock wrench tightening system Fits 2-1/2 inch by 2-1/2 inch box opening 10 inches long with a 1-1/4 inch hitch ball hole 5 inch drop and 3-1/2 inch rise 1300 pound tongue weight / 13,000 pound gross trailer weight