This rear end alignment kit features a 1-5/8'' precision center less-ground 72'' bar with 3-1/16'' O.D. gear case positioning/alignment collars and large bearing housing-end collars. This alignment tool makes 9'' rear-end assembly fast and precise. The rearend alignment collars fit into most standard 9'' Ford gears cases and all 3-1/16'' 9-Plus gear cases. The alignment collars accurately positions the housing ends true to the centerline of the gear carrier.