High quality wheels for Go Mini's Moving and Portable Storage Containers. Listing is for four (4) Service Caster heavy duty non-marking and non-marring 6 inch diameter by 3 inch wide red polyurethane tread on semi steel cast iron core wheels. Supports 2,000 pounds (lbs.) per wheel. When searching for a reliable and durable solution for your Go Mini's Moving and Portable Storage Containers replaement wheel needs, consider Service Caster’s polyurethane on semi steel cast iron core wheel. The non-marking, non-marring polyurethane tread performs especially well on hard surfaces such as concrete, tile, and wood, while the metal core wheel stands up to heavier loads with a stable and secure roll. Hardness scale 95 A Durometer. An excellent choice for clean environments. Service Caster is unsurpassed in quality, reliability, and excellent customer service. Count on us to move you forward.