The second, black layer, contains tiny particles that fill micro-pores in the steel so abrasive rust will not wear out the chain. Finally, a slick top-coat reduces dirt build-up, keeping your sprocket looking good. CAD designed and CNC laser cut to ensur Developed on the racetrack, with the goal of being both lightweight and strong enough to cope with the highest performance race machines. CAD designed and laser cut to ensure an exact fit on the wheel. Made in Supersproxs European factory, to their exacting standards, guarantees trouble-free riding. These sprockets include their exclusive Tri-Zinc anti-corrosion technology. The first layer is a silver / nickel coating providing a strong resistance to corrosion.