The Faxon Low Contour Gas Block is perfect for any rail system. These ultra-low profile gas blocks are the ideal companion for Faxon Firearms (or any other) barrels with a standard diameter gas journal. Made from high-strength steel, the gas blocks feature a matching black luster to Faxon's barrels. For lightweight builds, the block is drilled through the middle of the profile. The gas block clamps on to the barrel using 3 allen keys on the bottom of the block. NoteFaxon Firearms highly recommends the use of Loc-Tite or similar thread-locking compounds. Gas blocks will get very hot, so pick a compound according to your intended use of the firearm.