Imagine your office chair has no wheel caster, you would be carrying it right and left, install 4inch-Lock-Swivel-Caster-018 instead. Diameter of the caster wheel is a metric standard 100mm that is equal to 3.937" inch with imperial units. The wheel has a width of 50mm=1.969" inch. The overall height of the caster is 124mm or 4.882" inch. Top Plate is the method of installing the caster to your equipment, the dimensions are 138mm x 110mm x 10mm with the holes distance of 110mm x 75mm. Rolling with a wheel core material of Cast iron polyurethane and a Cast iron polyurethane tire rolled over Precision double ball bearing. Each caster will carry the load of 772 lb and is Swivel and Upper Locking type. Temperature range = -40 to 180 F. Enjoy our 4inch-Lock-Swivel-Caster-018, we wish all the best in your project.