Hampton 5/16 in. X 2-1/2 in. W X 4-3/16 in. L Coarse Zinc-Plated Steel U-Bolt, Pack of 10

U-bolt is a bolt bent into the shape of the letter "u." It's a curved bolt that features threads on each end. Because the bolt is curved, it fits nicely around pipes or tubing. That means U-bolts can secure piping or tubes to a support and work as a restraint.