... 50 2012 Heavy duty double ball bearing swivel pu castor Heavy Duty Caster /Four Size available (4'',5'', ... changed to Pvc,rubber ,nylon ,pp ,tpr ,cast iron,high-heat resistant material ,conductive wheel7.Applications: supermarket, display racks ... feature make it to be with abrasion -resistant and high shockproff.[Detailed Setting Explanation] Wheel DiameterCapacitySetting HeightPlate SizeHole ...