Has benefits of both steel and aluminum sprockets. Outlasts aluminum sprocket by 300%. Fits just like a stock sprocket. Weighs 50% less than all steel sprockets. 7075 T6 aluminum inner hub. Electro-less nickel coated carbon steel outer ring. Add to Favorite Sellers. Sign up to Newsletter. View more great items. This listing is currently undergoing maintenance, we apologise for any inconvenience caused.