U-Bolt 3/8 In. X 3 1/8 In. X 4 In. Square | Tie Down Engineering 86210 Tie Down Engineering U-Bolt 3/8 In. X 3 1/8 In. X 4 In. Square | 86210 U-Bolt 2 pack 3/8 inch-16 rod width/threads per inch 3-1/8 inch length between legs 4 inch leg length 1-3/4 inch thread length Designed to securely mount brackets to trailer frame Zinc plating prevents rusting and corrosion Includes flat washers and nyloc nuts