Fusion Dual Rear Sprocket 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 Engineered and manufactured in the Netherlands