... resistance 5.environmental products Product Feature:1.PU foam wheel/tyre: size 8''with pp rim2.customer required color,size,treat ... for wheelchair,scotter.etcRelated informationPU foam is a kind of one-part polyurethane sealant with high expansion rate and well ... function. 3. No cracking after curing of PU foam with good sealing. 4. Good adhesion with surface of aluminum alloy, concrete, coatings, ...