Wheel casters like the 3inch-Lock-Swivel-Caster-018 are used to roll your built machine or equipment back and forth. This caster is rolled on a wheel that has 75mm diameter/2.953" inch inches. The wheel has a width of 21mm=.827" inch. The Caster with the wheel from end to end is 104mm = 4.094" inch. Top Plate is the method of installing the caster to your equipment, the dimensions are 65mm x 65mm with the holes distance of 49mm x 49mm. Low drag was achieved by a Grey rubber core on a Grey rubber tire spinning freely with a Plain bearing. Here come the maximum load that should be applied on every wheel, remember to add safety factor, when calculating the load capacity 66 lb with a Swivel and Upper Locking type. Last and not least the temperature range = -40 to 180 F. Enjoy our 3inch-Lock-Swivel-Caster-018, we wish all the best in your project.