These are no ordinary bicycle tubes! These extra strong inner tubes stop flats for 2 years because there is Slime inside. Works in bicycles, wheelbarrows, wheelchairs, jogging strollers, snow blowers and much more. No more flats for 2 years! Extra strong with Slime sealant inside. Instantly seals tread area punctures up to 1/8″ (3mm) in size. Seals multiple punctures repeatedly. 20” x 1.50-2.125” Schrader