The Faxon Firearms GBALP6253 Low Profile Adjustable Gas Block for AR-15 is designed for precise gas system tuning. Compatible with barrels featuring a .625\" gas journal. Patent-pending anti-fouling adjustment screw design. Secure three set screw mounting system. Built from high-strength steel for reliability. Notable features include adjustments for tuning gas flow and a compact low-profile design for lightweight builds. This item is not available to ship to California.