GEMTECH flash hiders are the culmination of user feedback extensive testing and decades of experience. The new flash hiders are more aggressive than ever to cut down on carbon build-up in your suppressor and to prevent it from getting stuck.Features: Increased size of 3/4" wrench flats for installation Blank Firing Adapter (BFA) groove for increased silencer options and training Extended area behind lugs for use on short barrel rifles Overall length of 2.4" for use on 14.5" barrels (pre-drilled for pinning) Precision mounting shim kit included Built in carbon cutting grooves Quickmount lugs for use with all GEMTECH 5.56mm and .30cal suppressors