4inch-Swivel-Caster-048 is a wheel caster, which is the shortcut of installing wheels on a hospital bed, or any object needed to be moved. This caster is rolled on a wheel that has 100mm diameter/4" inch inches. This wheel caster can be mounted using a with the dimensions of 95mm x 70mm and holes distance of 75mm x 52mm. Rolling with a wheel core material of Polyurethane and a Polyurethane tire rolled over Ball bearing. Each caster will carry the load of 218 lb and is Swivel type. Last and not least the temperature range = -40 to 180 F. Remember, you will have to buy the 4inch-Swivel-Caster-048 in order to have it :).