Supersprox goes all out with their Rear Steel Sprockets, from first stage to last. Let's start with the first. Supersprox begins by using a highly specialized SCM435 Ni-Chrome-Molybdenum low-corrosion type steel as the base material for the sprocket. Once the shape has been CNC machined, the sprocket is case hardened to give it a low carbon core and an incredibly tough surface hardness. To finish it off Supersprox uses hot-dip galvanizing to protect the surface of the sprocket by chemically creating a shielding layer of zinc carbonate. So what does all that mean? What it means is that you're getting a sprocket with outstanding durability made from some of the best materials available.