Vehicle Compatibility: These SumoSprings are specifically designed to fit towing or hauling trailers; The SSR-623-47 pairs seamlessly with your factory suspension system Reliable Load Support: Designed for trailer frames with a GAWR of 3,000-5,000 lbs; To maintain full memory rebound and long-term performance, avoid compressing beyond 70% of the spring’s original height Smoother Ride: SumoSprings require no maintenance thanks to their proprietary closed-cell micro-cellular urethane construction; This delivers a smooth, progressive spring rate for a safer and more comfortable hauling or towing experience Rear Stability: Prevents rear sag and reduces body sway to keep your trailer level and stable under heavy loads; Enhances safety and handling by minimizing roll, especially during sharp turns and in crosswinds, for greater driver confidence Peace of Mind: Proudly made in the USA, these springs require no air lines, compressors or maintenance — just install and haul, backed by a lifetime warranty for long-term peace of mind