it is Patented Bolt-on Design, silent Ride Polyurethane Stability Blocks, Plated And Powder Coated Components And Easy To Follow Installation Instructions Make This The Helper Spring Of Choice For Do It Yourself And Professionals Alike. Manufactured With Heat Treated Alloy Spring Steel In Our California Based Facility, These Units Increase Your Vehicles Level Load Carrying Capacity Up To The manufacturer Gross Vehicle Weight Rating. With Its Progressive Rate Design This Helper Spring System Enables Trucks And Vans To Carry Loads With More Control And Stability. As Your Load Increases This Spring Automatically Increases Its Rate To Resist Sagging And Tail Dragging.

Product Features:

• Manufactured With Heat Treated Alloy Spring Steel
• 2500 Pounds Level Load Capacity
• Progressive Rate Leaves Do Not Effect The Ride When Unloaded
• Never Needs Adjusting
• Silent Ride, With Unique Polyurethane Block Applies Tension To The U-bolts To Maintain A Quiet Ride, Also Stabilizes The Helper Spring In Reverse Or Rebound Mode
• Heavy-duty Hardware
• Simple Bolt-on Installation