Butterfly shaft. Fits late style Hypercharger with bearing on the shaft only. Note: Replacement parts for your Late or Early style Standard Hypercharger air cleaner. For the Early and Late Hypercharger all parts are identical; except the early style case halves and the butterfly shaft & bushings are different. The Late style uses bearings on the butterfly shafts; the early style uses bushings on the butterfly shaft. Note: Parts specific for ''early style'' only Hyperchargers are no longer available.