ICON 2007+ Toyota Tundra Rear Leaf Spring Expansion Pack KitUnlike traditional add a leafs that obtain lift height at the cost of stiffening the spring rate and sacrificing ride quality, the 2007 2021 Toyota Tundra Rear Leaf Spring Expansion Pack replaces all the factory secondary leaves while only retaining the factory main and overload springs. This allows us to soften the spring rate to increase ride comfort while also increasing ride height, maintaining load and towing capacities, and increasing wheel