2012-Newer Aluminum Steer for 22.5 inch and for 24.5 inch Aluminum Wheel This is the most popular Centramatic for Semi use Centramatic's patented "On-Board" balancing technology is time tested and proven to increase tire life, reduce maintenance cost and increase fuel economy by constantly balancing the complete wheel assembly. Our balancers improve tire balance, wheel balance, and complete assembly balance. Smoother Ride Increases tire life 25%-50% Reduces vibration Helps prevent tire cupping No pre-balancing required Lower tire operating temps 8%-10% ******Five Year Warranty*******