Leaf Spring Add-a-Leafs will add a single or a few pieces of spring steel to the leaf spring packs to either lift the vehicle or help with load control. They are installed by removing the center pin and install the Add-a-Leafs into the spring pack with a longer center pin. WARNING: Make sure to securely c-clamp the leaf pack together before removing the factory center pin as the leaf springs are under tension. Then slowly loosen c-clamps to allow the new Add-a-Leaf to be inserted. Always have a professional mechanic perform any modifications to the vehicle.