Sunstar's Works Triplestar line of aluminum rear sprockets have been the most durable, lightweight aluminum series for over 25 years. Made from 7075-T6 aluminum and with an extra-thick hard anodized coating, Sunstar users get 15-20 percentage longer life vs 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.