U-bolt Kit for Mounting 3,500-lb, Round Trailer Axles - 5-1/2" Long U-bolts Go to amazon.com Related posts Which is the best u-bolts round? FeatureKit Includes(4) 5-1/2" Long U-bolts(2) U-Bolt plates for 1-3/4" springs(8) 1/2"-20 Hex nuts