This is a pack of 50 heavy-duty lock nuts. They're 1/2-13 USS coarse thread, which is a common size for bigger bolts. The 'Grade 8' rating means they're made from alloy steel, quenched and tempered for high strength, with a minimum tensile strength of 150,000 PSI – so they're tough. They're Nylock nuts, which means they have a nylon ring insert inside. When you screw them onto a bolt, the nylon grips the threads, creating friction that helps prevent the nut from loosening due to vibration. That makes them perfect for automotive, machinery, trailers, or any application where things shake a lot. They have a yellow chromate zinc coating for corrosion resistance. A solid, reliable pack of nuts for serious projects. Note: The description says both 50 pieces and 25 pieces – the pack is likely 50, but double-check the listing.
