MASTER GRADE AR15 CROWFOOT ARMORERS WRENCHES Now you can say Ive got a wrench for that No more rigging and adapting generic wrenches to complete your builds. MasterFit 12 Drive Crowfoot Wrenches are purpose built and specialized for precise fitment to confidently deliver torque to the most common MILSPEC assembly nuts. Titanium coated stainless steel construction provides tight tolerances for solid nutgripping strength and enhanced noslip tool control.