they are fully adjustable for a great ride. Air Lift air springs eliminate sag, sway, and bottoming out. They are made with rugged, durable components for long, reliable service. LoadLifter 5000 Heavy Half-Ton adjustable kits are Air Lift's heaviest-rated kits for hauling or towing heavy loads. They have leveling capacity right up to the manufacturer's recommended Gross Vehicle Weight Rating, and are air adjustable from 5 to 100 PSI. LoadLifter 5000 Heavy Half-Ton adjustable kits fit such popular vehicles as 1/2, ton and one-ton pickup trucks, many Class A, B & C motor homes, and commercial trucks and other severe uses. They also come standard with a limited lifetime warranty and an exclusive 60 day ride satisfaction guarantee.