1.Good for installation 2.High strength of threads 3.High strength of resistant Woonden sleeper screw spike: ss8, ss25, ss36 and other specifications screw spikesProduct Name: Woonden sleeper screw spikes(rail spike, railroad spike railway fastener)1. Surface treatment: Nuture, black, pot galvanizing, cold galvanizing, oil, parkerising etc.2. Grade: 4.6, 5.6, 8.8, 10.6 and12.93. Dia: from M16 to ...