These are custom large 316 stainless u-bolts we supplied our customer in San Diego. They specialize in waterworks related construction and specifically needed 316 stainless steel material with a fast turnaround. We were able to ship the parts within 4 days of order confirmation. 1/2" diameter bar stock was used with 2 inches of coarse thread on each leg, with inside width measuring 16.25" and inside length at 18".