Renthal Off-Road Rear chainwheels are manufactured from a specially enhanced 7075 T6 aluminum alloy produced especially for chainwheeels. This particular alloy has excellent resistance to wear combined with a very high tensile strength. Renthal chainwheels are designed to withstand the rigors of Motocross and Supercross racing. Renthal Off-Road Rear Chainwheels feature: Precision CNC machining for uneaqualed accuracy of fit, tooth profile and concentricity. An "ultrlite" design reducing unnecessary weight while retaining maximum stength. Aluminum (one-third the weight of steel) which reduces the power required to acclerate and brake unsprung revolving weight, resulting in improved race performance. Self-cleaning mud groves in between each tooth. A silver etched finish, resisting dirt build up.