Product information updated on 2021-11-10, Manufactured by Air lift - Part Number AIR:89338, 2011-19 Silverado/Sierra 2500HD/3500HD AirLift LoadLifter 5000 Ultimate Plus with stainless steel air lines, The Air Lift internal, jounce bumper helps to absorb shock even with zero air pressure! And who doesn't want stainless steel parts? Especially when they protect your system from the road's rage. All the benefits of the LoadLifter 5000 series with the addition of an internal bumpstop in the bags and stainless steel air lines., LoadLifter5000 Air Spring Kit by Air Lifts are specifically engineered for hauling or towing heavy loads. LoadLifter 5000 air springs are designed to fit popular vehicles and pickup trucks, motor homes, commercial trucks and other severe uses.