This is a square U bolt in 304 stainless steel that we supplied to a customer at just 32 pieces. The 2 inches of thread on either side are 5/16-18 coarse thread and the inside depth of the part is 7-1/2 inches, while the inside diameter is at 6-1/16 inches. Also a rush project, these parts were completed within 3 days as well from order.