Wheel casters like the 3inch-Caster-013 are used to roll your built machine or equipment back and forth. Diameter of the caster wheel is a metric standard 75mm that is equal to 2.953" inch with imperial units. The thickness of the wheel is 40mm or 1.575" inch. The Caster with the wheel from end to end is 195mm = 7.677" inch. This wheel caster can be mounted using a Top Plate with the dimensions of 110mm x 100mm x 4mm fork:3.5mm and holes distance of 85mm x 75mm. The caster core is made of Polypropylene and has a Polypropylene tire with a low friction ball bearing. Here come the maximum load that should be applied on every wheel, remember to add safety factor, when calculating the load capacity 441 lb with a Fixed type. Last and not least the temperature range = -40 to 180 F. Remember, you will have to buy the 3inch-Caster-013 in order to have it :).