This Hellwig Helper Spring set the standard for all other aftermarket helper springs. Featuring Progressive Spring Rate and Fulltime Spring Rate design, this spring is the workhorse of the Hellwig Spring line. With the Progressive design the vehicle must be loaded and its spring compressed to activate the Hellwig Spring, therefore as the vehicles load increases the Hellwig Helper Spring progressively increases its resistance to the load. In the Fulltime design the Hellwig Spring immediately reacts to the vehicles load, therefore compressing very little as load is applied to the vehicle. Manufactured with heat treated ASTM 5160 alloy spring steel these units increase your vehicles level load carrying capacity up to the manufacturer’s Gross Vehicle Weight Rating. Designed to install on full size pick-up trucks and vans, this unit requires mounting hardware to accommodate 2 1/2? or 3? wide leaf springs. When ordering be sure to identify the spring kit and the appropriate mounting hardware kit to complete the installation. Simple bolt on design using common hand tools provide the installer ease of installation and the vehicle owner hassle free use. “Set it and forget it”. The LP 25 is rated at 2500lbs level load carrying capacity and the LP 35 is rated at 3500lbs level load carrying capacity, not exceed the vehicles Gross Vehicle Weight Rating.