... . NANTE has two main manufacture bases, 5 main factories with 12 product lines of machining, welding, heat treatment, assembly, painting, casting ... nuts(1)Grade: 4.8 -- 12.9,A2, A4(2)Size: M3-M72(3)Finish:plain, zinc plated, hot dip galvanized, dacroment ... export packing or According to customer's requirement NANTE 40cr 12.9grade track bolt and nut