These commercial quality skates feature top grade steel, the most robust 3″ castors available, are quick and easy assembly. Our Tire Skates have ball bearings on the swivel (which all casters have) AND on the axle shaft. It rolls with less than 1/2 the force of a standard caster. Today"s technology housed in a robust design will provide you with years of service and mobility. We stand behind every product we sell by providing quality products to you. Features: Includes four (4) 12″ tire skates, One person can easily handle and move a 3 ton vehicle, 12″ x 16″ Solid Steel Plate–X Large–not the 8″ you see elsewhere, Powder Coated–not painted, Won"t chip/scratch, 3″ Premium Ball Bearing Castors, Rated at 6000 lbs., Integrated hole in the top of the skate for easy storage–mounts onto a hook in your garage, Professional/Mechanic Quality – not like the competition, Minor assembly is required–installation of the 3″ ball bearing wheels.