Japanese Engineered Spring Loaded Towing Casters are one of the only in the market specially designed for spring-loading AND towing applications. Its high-performance polyurethane is abrasion resistant and tolerates longer distances, while providing great absorption. The state-of-the art caster raceway is made up of both a radial bearing that allows for smooth operation for towing applications, and a thrust bearing, which provides paramount absorption for heavy loads. The springs provide extra support for sensitive product. Yellow tread color. 92 +/-5 Shore A. Made in China.