This Jack Base is designed especially to accommodate larger tires. It is made from a single block of polymer to provide a stable position. Molded indentation designed to fit your factory scissor jack to keep it planted firmly in place when jacking the vehicle. Used as a stable base to help lift and extend the range of the production jack when vehicle is equipped with larger tires and/or lift kits are present. Angled face can also be used a wheel chock.