FLANGE NUTS SERRATED 1/4-20, 5/16-18, 3/8-16, ZCN3, Coarse ZINC PLATED STEEL HEX
1/4″-20, 5/16″-18, 3/8”-16, ZINC PLATED STEEL HEX SERRATED FLANGE Nut Rohs3, NC HARD/SERR. Serrated for extra grip. Nut with a wide flange. Picture shown above is example and each length have different amount of threads are on the shaft thread are decreases as length increases.