You need 4inch-Lock-Swivel-Caster-008 to have your office desk, equipment or even a machine to easily roll them around. This caster is rolled on a wheel that has 100mm diameter/3.937" inch inches. Dimensions of the caster wheel is 50mm (1.969" inch). The Caster with the wheel from end to end is 150mm = 5.906" inch. Mounted via a Top Plate that has the size of 115mm x 100mm x 6mm and the holes distance of 72mm x 85mm. The Roller bearing design will enable the Cast Iron and Polyurethane tire to roll easily with a core made of Cast Iron and Polyurethane. Bearing in mind that every caster wheel has the load capacity of 661 lb with a Swivel and Center Locking type. Last and not least the temperature range = -40 to 180 F. Remember, you will have to buy the 4inch-Lock-Swivel-Caster-008 in order to have it :).