AR-15 Barrel Nut Hand Guard Tension Clutch Ring Barrier Defense leads the industry in cutting edge AR technology and has found a way to improve the reliability and re-usability of your free floating or mil-spec barrel nut. For all mil-spec AR barrels, this reverse stainless barrel nut tension clutch ring expands as the barrel nut is tightened giving you that extra little tweak needed to align the gas tube to the upper receiver without damaging the threads. No more damaged barrel nuts!! Each ring is re-usable for about 3 installations and best of all, no more thread stress. Breath new life in to old hand guards. They are custom made for Barrier Defense and are reversed for tightening. Kit includes (1) ring. Comes with the Barrier Defense lifetime warranty! ****Know your states laws when purchasing gun parts.****