The United States Court of Appeals for the Third Circuit has recently held that part numbers are not protectable under copyright law. The Court held that, first, the particular part numbers at issue were not original, which a prerequisite for copyright protection. Significantly, the Court also held that part numbers are ineligible for copyright protection at all because they are analogous to short phrases or titles, which are also not copyrightable. Southco, Inc. v. Kanebridge Corp., 390 F.3d 276(3d Cir. 2004). This is a departure from earlier opinions holding that part numbers were eligible for copyright protection under certain conditions. As a result, manufacturers at this time cannot rely on copyright law to stop competitors from using their part numbers on packaging or in catalogs or on interchange sheets. The best protection for part numbers is to obtain federal trademark registrations for those part numbers that qualify as trademarks. In addition, unfair competition law still prevents competitors from using part numbers in a way that results in passing off.