This SES Suspension Upgrade can be adapted to fit the rear suspension of most heavy-duty tow trucks equipped with a Neway tandem suspension. Each laser cut piece of steel is precision bent and powder-coated to ensure a quality fit. We’ve engineered our hollow rubber springs to deliver a progressive spring rate. In other words, the more weight that pushes down on the rubber springs the harder they work to prevent rear end sag, and help stabilize the load.