Tens of thousands of different kinds to select from to have your office Desk/chair sliding easily right and left, install the VXB005100BC. Diameter size of the caster wheel has a metric standard 100mm which is equal to 3.937" inch with imperial units. Dimensions of the caster wheel is 50mm (1.969" inch). The caster dimensions heightwise is 142mm/5.591" inch. Mounted via a Top Plate that has the size of 100mm x 115mm and the holes distance of 75mm x 85mm. Low drag was achieved by a Black Cast iron core on a Black Cast iron tire spinning freely with a Roller bearing. Each caster will carry the load of 441 lb and is Swivel type. Temperature range is -40 to 180 F. Very important notice, you need to buy the VXB005100BC in order to get one :).