These are no ordinary bicycle tubes! These extra strong inner tubes stop flats for 2 years because there is Slime inside. Slime Smart Tube Schrader Valve Bicycle Tube (16 X 1.75-2.125) - 30051:Works in bicycles wheelbarrows wheelchairs jogging strollers snow blowers and much more. Stop flats for 2 years! Between the dozens of size options and the various valve stem types (Presta what is that) selecting the correct tube for your bike can be challenging. Check out our quick tube guide to help you select the perfect tire tube for your bicycle every time.