Sutong China Tires Resources TU4008 HI-RUN Heavy Duty Lawn and Garden Tube, 18/850-8 Tr13 Lawn and garden tube Fits 18x8.50-8, 18x9.50-8, 20x10.00-8, 21x12.00-8 and 22x11.00-8 Tr13 valve stem 18/850/950-8-Inch Tube