The Aero Precision low profile gas block is manufactured from hardened 4150 chrome moly steel with a durable phosphate finish to protect against wear and corrosion for the entire lifespan of your rifle. With a low-profile design to fit under almost any free float handguard on the market, so you can fully customize your rifle. These AR-15 gas blocks are made in the U.S.A. and include a set of steel 10-32 x 3/16 knurled cup point set screws for securely attaching them to your barrel. With precise machining tolerances, you can expect perfect match to your barrel with .875” gas block journal and is compatible with all rifle and carbine length gas tubes. The time is now to upgrade your AR-15 and the Aero Precision low profile gas block is the solution if you plan on free floating your barrel.