The Yankee Hill Phantom M14 QD Flash Hider with Sight Base is designed to replace the standard M14 flash hider and sight assembly. Simply remove your stock flash hider or sight assembly, reinstall your stock sight post onto the mount, and install the new assembly onto the barrel. It is as simple as that! the Flash Hider is used in conjunction with the Phantom 7.62 Q.D. Sound Suppressor. It retains the excellent flash hiding capabilities of the original Phantom. This Phantom flash hider will NOT accommodate the 5.56 Sound Suppressor. (Sight base does not fit models with 18.5 inches or shorter barrels).