... free 2.longer service life 3.high load capacity 4.light weight,acid and base resistant Pu foamed wheel 12x3.50-5"Detailed technical ... ,hand truck, and trolley2. abrasion resistance, corrosion resistance and higher flow rate3. polyurethane tires with the benefit of never going flat ... .We are sincerely looking forward to be your supplier.Size for sale: 6'',8'',8.7",10'',12'',13'',14'',15'',16 ...