Increases safety,500 lbs. Capacity at 50 Percent Compression,Compress Up To 80 Pct. Of Original Height w/Full Memory Rebound,Sold as a pair left and right,Worlds Only Leakproof Air Spring,Reduces overall cost of ownership,Improves Overall Driver Control And Ride Comfort,Requires no maintenance; Proudly made in the U.S.A.,Made From Patented Microcellular Urethane,Reduces And Absorbs Vibration,Never Load Any Vehicle Beyond The Manufacturers GVWR,Progressive Spring Rate