The NBS knurled ejection port cover rod allows you to install a mil-spec style ejection port cover without having to install the tiny c-clip that holds the rod in place. The end of the rod is knurled, preventing the rod from passing through the hole in the upper receiver. This method makes building your upper faster and easier!Features:Manufactured to mil-spec dimensionsFits all common AR15 and M16 upper receiversEjection port (dust cover)Knurled ejection port rod - Improved with larger knurling!Ejection port springPhosphate coatedWeight .8 ounces100% USA Made