This kit pairs a mil-spec barrel nut with a wrench that does more than one job. The wrench is 4140 steel with a hardened manganese phosphate coating, and it handles castle nuts in any style tube, .750 flash hider flats, and A2 rifle buffer tubes. It takes a 1/2-inch breaker bar for torque, and it includes 3/16-inch and 3/8-inch hex drivers for grips and scope mounts. If you’re setting up a bench, this covers most of what an AR build asks for.