Steel brackets bolt to 3" dia. axle tubes. Narrow rings are useful for securing bird cages. Grade 5 hardware included with Nyloc nuts.Pit Stop USA offers Allstar Performance Clamp-On Ring, Retainer - 1" Wide, 2 Bolt Tube ALL60144 at low everyday prices. Be sure to check out all of our products from Allstar Performance including Allstar Performance Tube Clamps.