Our Dana 60 bronze upper kingpin bushings have been engineered to take the place of the factory plastic bushings that can fail under heavy use. If you are hard on your rig, these are a great upgrade for added reliability. Only to be used with aftermarket high steer arms or kits that eliminate the factory kingpin cap and spring. Manufactured from high quality materials. Machined to insure proper distribution of lubrication. Stops "wobble" of factory knuckles. Threaded holes on top for easier dis-assembly. Will work with various kingpin Dana 60 axles