The most useful tool on your gun bench is the AR-STONER Armorer's Wrench. This multi-tool is designed to perform many jobs for building and maintaining your AR- This streamlined tool includes a barrel nut wrench, flash hider wrench and buffer tube lock ring wrench. FeaturesHeat Treated SteelMultiple Applications For Installing Or AdjustingUse For Mil Spec Barrel Nuts, Flash Hiders, Muzzlebrakes, Handguard Barrel Nuts (Ultralight/Airlite Series), Castle NutsAll In One Tool To Completely Take Down/ Disassemble