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 & much more. No more flats for 2 years! Extra strong with Slime sealant inside Instantly seals tread area punctures up to 1/8& Prime; (3mm) in size Seals multiple punctures repeatedly 27.5 x 2.0-2.40 Schrader Schrader valve stem Pre-filled with puncture stopping Slime tube sealant Non-toxic & non-flammable Cleans up with water Prevents flats for 2 years!