SuperSprings Trailer SumoSprings utilize the same micro-cellular air springs as SumoSprings. They mount above trailer leaf spring assemblies and create a cushion between the axle and trailer frame. Trailer SumoSprings reduce wear and tear on body frames, windows, doors, closets, mounted TVs, and other components by minimizing bounce, hop, and sway associated with most towable RVs. Reduced sway and bounce in the trailer results in increased driver control, ride comfort, reduced maintenance costs, and reduced overall cost of trailer ownership. Trailer SumoSprings are a maintenance-free suspension enhancement built to create a better journey by reducing G-force in your towable by 68%. Handmade from micro-cellular polyurethane, they are designed to remove sway, hop, and body roll while increasing overall driver control and comfort while towing. The TSS-107-47 is designed for trailer frames with a GAWR of 5, 000-8, 000 lbs. with the spring sitting on top of the axle tube. The Black SumoSprings shouldn't be compressed past 65% of their original height in order to keep full memory rebound. NOTE: This product is designed to work on most trailers with the springs mounted above the axle. The factory spring plate must not be wider than 4-1/4". Because of the varying build designs from different trailer manufacturers, there are occasionally some models that this product will not fit. For installation of Trailer SumoSprings the gap between the top of spring plate and bottom of the frame must be between 5.3" and 6.55".SpecificationsWeight: 13 lbs. Dimensions: 13" Ã 8" Ã 5"Spring Diameter: 3"Spring Height: 4"Capacity: 1800 lbs. at 50% Compression Handmade from micro-cellular polyurethane Designed to remove sway, hop, and body roll while increasing driver control For trailer frames with 5, 000 to 8, 000 lbs. GAWR with spring sitting on top of axle tube | SuperSprings TSS-107-47 Trailer SumoSprings, Over Axle 5-8K in Black