Real Avid Master-Fit Wrench Set, Wrench, Stainless Steel, AR15 Crowfoot AVMF13WS The most comprehensive all-in-one AR15 Armorer's Torque Wrench Kit ever assembled. Master-Fit single-purpose crowfoot wrenches are made specifically for the job. Specialized for precise fitment and manipulation of MIL-SPEC and free-float barrel nuts" muzzle devices and castle nuts. Titanium-coated stainless steel construction provides tight tolerances for solid nut-gripping strength and enhanced no-slip tool control. Paired with the heavy-duty Master-Fit Torque Wrench" it takes Gun DIY building to a new level of Master Grade quality and precision. It's time to raise your Gun Tool Expectations and upgrade to Master Grade!