5/16-18 nylon lock nut. Coarse. Zinc. Low-carbon steel. Thread Type: Coarse, Thread Diameter: 5/16", Threads Per Inch: 18 tpi, Material: Steel, Finish: Zinc, Pkg Qty: 100 No. 180153: Thread Type: Coarse, Thread Diameter: 3/8", Threads Per Inch: 16 tpi, Material: Steel, Finish: Zinc, Pkg Qty: 100 No. 180156: Thread Type: Coarse, Thread Diameter: 7/16", Threads Per Inch: 14 tpi, Material: Steel, Finish: Zinc, Pkg Qty: 50 No. 180159: Thread Type: Coarse, Thread Diameter: 1/2", Threads Per Inch: 13 tpi, Material: Steel, Finish: Zinc, Pkg Qty: 50 No. 180165: Thread Type: Coarse, Thread Diameter: 5/8", Threads Per Inch: 11 tpi, Material: Steel, Finish: Zinc, Pkg Qty: 25 No. 180168: Thread Type: Coarse, Thread Diameter: 3/4", Threads Per Inch: 10 tpi, Material: Steel, Finish: Zinc, Pkg Qty: 20