– Special hardened and nickel coated steel outer ring.- Will outlast an aluminium sprocket up to 3 times- 50% less weight compared to a normal steel sprocket.- Aircraft-grade 7075-T6 aluminium carrier.- Precise manufactured outer ring and carrier interlock permanently using a specialized heat-shrink procedure.- Carrier is colour anodized coated for extra durability.- CAD designed, CNC machined and laser cut using state of the art technology.Made in Holland