PFC 3/4"-10 NC x 2-1/4" Grade A Regular Coupling Nuts Zinc Plated - 20 per Box Coupling Nuts for 3/4" Diameter with 10 NC Thread (National Course) Bolts 2-1/4" Length Grade A Low Carbon Steel Coupling Nut (Meets ASTM A563) Zinc Plated to meet ASTM F1941 FeZn3A 20 per Box