Sunstar's new Works Triplestar black aluminum rear sprocket features most of the same great features as the famous hard anodized version, only that it is black anodized for a great looking color finish. Made from 7075-T6 aluminum and with an extra-thick black color anodized coating, Sunstar users get 15-20 percentage longer life versus other options. Computer designed weight reduction holes and an exclusive tooth-valley design that provides up to 50 percentage more chain roller contact area results in the lightest, most stable aluminum sprocket possible.