Compatibility:High Quality 16" X 2.125" Kids Bike Inner & Outer Tires are compatible with RoyalBaby, Joystar, Dynacraft and other kid’s bikes with 16'' tires High Quality:16 x 1.75/2.125 Kids Bike Tire & Inner Tube Set is made of high quality butyl rubber with better stretch and shock absorption, which can make you more smooth and comfortable while riding. It also has better impact and puncture resistance, which is not easy to be damaged and can be used for a long time Superior Air Tightness: Butyl rubber inner tubes have better air tightness and can last up to 6 months under normal use without leaking. Traditional rubber's air permeability means you often need to reinflate your inner tubes as often as every 30-45 days New Upgrades: The tube's straight stem features an enhanced seat seal to prevent sand and dust from entering the tube and tire. also tear-resistant, extending the service life of the valve and ensuring that the inner tube does not leak for a long time Packing Include: 2*16 ×2.125 tire + 2*16X1.75/2.125 inner tube + 2*Tire Levers, help you install inner and outer tires more conveniently and quickly new