... No:EF-ZB02/ EF-ZB03 Material:Nylon,PU, Rubber, Super artificial rubber. Size:v2' -5inche Caster is important compoent of Wei Tao ... system,which commonly used in worktables, carts,racks.There is caster iron rubber wheel ,super artificial rubber wheel ,PPwheel,phenolicaldehyde wheel ... . It's divide two style:With brake &Without brake PU &Nylon caster and wheel for industrial trolly