Supersprings Trailer SumoSprings are designed to enhance your trailers load carrying ability, stabilize sway, and improve overall driver control and comfort. Trailer SumoSprings are maintenance free and do not require any airlines or compressors. The air inside Sumosprings is captured in millions of air pockets inside the micro-cellular urethane material. This means that there will be no leaking or rupturing like traditional air bags. Supersprings Trailer SumoSprings are a one-piece unit and only mount at one end. Solo Supersprings come in blue and black. Blue ones are designed for trailer frames with a GAWR of 3,000-5,000 lbs with the spring sitting underneath the axle tube. The Blue SumoSprings shouldn't be compressed past 70% of their original height in order to keep full memory rebound. Black ones are designed for trailer frames with a GAWR of 5,000-8,000 lbs with the spring sitting on top of the axle tube | SuperSprings Trailer SumoSprings TSS-107-47