Air Loc Brand Tire Inner Tube with TR13 valve stem - 8 inch Combination Size Fits 18x8.50-8, 18x850-8, 18x9.50-8, 18x950-8, 20x8.00-8, 20x800-8, 20x10-8 Lawn and Garden Designed for Lawnmowers, Go Carts, ATVs, etc. Fits Sizes: 18x8.50-8, 18x9.50-8, 20x8.00-8, 20x10-8 Tube has Standard TR13 valve stem: Straight rubber valve, the most common stem style, measuring approx. 1.38" long and used in the standard size wheel hole of approx. 1/2"