this invention is directed to protection against theft or other unauthorized removal of articles secured by threaded nuts or the like , particularly truck tires . a tamper - proof fastener is provided having a locking cap which engages the underlying lug bolt and a seal which surrounds the locking cap and the lug nut of the tire to be secured . the seal rotates freely about the locking cap and the lug nut so as to prevent anyone from loosening the lug nut without first breaking the seal .