Poly Foam Filled Wheels 3.00-4 Is Mainly Used As The Wheels Of Electric Wheelchairs. Its Tire Consists of Two Parts: Rubber Outer Tube, Microcellular Polyurethane Elastomer Filled or Inserted inside. The Brand Of Rubber Tires mainly is Cheng shin Or Innova. Its Max. Loading Is About 75KGS per Wheel.
link:http://www.pu-tire.com