"FOUR THRU HOLES AT THE CORNERS AND TWO BRACKETS, ONE CENTERED ON THE WIDTH ON EACH SIDE; THE OUTERMOST HOLES IN EACH BRACKET HAVE A 0.79"" X 0.10"" TUBE BETWEEN THEM; A 0.5"" X 5.5"" UNC 8.8 IS0 898 STEEL ZINC PLATED BOLT WITH WASHERS AND A NYLON INSERT LOCKNUT GOES THRU THE TUBEGOES THRU THE TUBE A 0.79"" X 0.10"" TUBE WITH A 0.5"" X 5.5"" UNC 8.8 IS0 898 STEEL, ZINC PLATED BOLT WITH NYLON INSERT LOCKNUT AND WASHERS THRU IT"