NcStar’s AR15 Armorer’s Barrel Wrench is a generation 2 combo tool with many tools to work and upgrade your AR-15 M4 and M16. It features a barrel wrench for GI Barrel Nut free-float barrel nuts with GI spacing DD barrel nuts and YHM ( 1 3/4″) Spanner wrench A2 (3/4″) and 5/8 Flash Suppressor wrench M4 Collapsible stock castle nut wrench A2 buffer tube wrench a flat blade screw driver for A2 buttstock plate 1/2″ and 3/8″ drive compatible lower receiver push pin tool and 1/4″ hex bit drive socket 1911 barrel bushing wrench with a tactical bottle opener. All tools are clearly labeled.