This SES Suspension Upgrade fits the front suspension of a Chevrolet Silverado 1500/2500/3500 & GMC Sierra 1500/2500/3500 truck (see below for full list of applications). Each laser-cut piece of steel is 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 (weight from a snowplow or heavy aftermarket accessories – such as a steel bumper) the harder they work to prevent front-end sag. GMFK25S* replaces the bumpstops on the front suspension of the 1996-2010 GMC Sierra and Chevy Silverado K2500 4WD pickup truck models with cast lower control arm.This kit is rated at 14,000 lbs capacity. Even though you're increasing the spring rate by adding this upgrade, this does not increase the GVWR (Gross Vehicle Weight Rating). Please make sure that the load does not exceed the GVWR set by the manufacturer.