Here are nylon core polyurethane caster wheels, 6x2 inch wheels with double ball bearing. Heavy duty swivel casters and rigid casters. They belong to our spanish client with special customization. Each of them can load 770lbs/350kg at most. Normally the load capacity of 6" heavy duty casters are less than 660lbs/300kg. Thickened ball turntable ensure that. They are made to suit the rolling containers. Of cousre, you can use them other ways. You can find more here this web or contact us.