DO NOT ACCEPT THIS PRODUCT! Would give ZERO stars if the system allows it! I stopped at Discount Tire to have them professionally fitted as I just bought new tires. pneumatic wrench, then tighten to specification with a hand torque wrench. as with all installations. As soon as they made the first pull with a torque wrench, the top of the chrome grommet immediately came loose. WEAK metal and money down the drain! DO NOT BUY THIS PRODUCT!