Brighton-Best 1/2"-13 NC Grade A Finished Hex Nuts Zinc Plated - 50 per Box (319125)Nuts for 1/2" Diameter with 13 NC Thread (National Course) BoltsGrade A Low Carbon Steel Hex Nut (Meets ASTM A563 & ASME / ANSI B18.2.2)Zinc Plated to meet ASTM F1941...