... plated: colorful , white and blue ,black,Zinc And Nicke name: notch plusnutspecification: M3-M12material: steelzinc plated: colorful , white and blue ,blacktype ... : body with open notch, head with notchwe use cold forged technique, not only save ... ,5/16,3/8 . material: steel, stainless steel, brass,aluminium notch plus nut