This 20 piece set of red lug nuts from Rugged Ridge have a 19mm hex head and 1/2" - 20 thread. All Rugged Ridge wheel lug nuts are designed and constructed to meet strict engineering quality standards. Each lug nut is double-coated for high corrosion resistance to combat rust in any environment.. This 20 piece set of red lug nuts from Rugged Ridge have a 19mm hex head and 1/2" - 20 thread.