Size: 16x2.125 Replacement inner tube, also fits 16x1.75 16X1.95 16x2.10 16x2.125 tires; Fits vehicle with 16 inch tires and wide between 1.75 to 2.125 inch tires; Please confirm your existing tube size to ensure that they are properly replaced Wide Compatibility: These heavy duty 16x1.75/2.125 inner tube Fits most 16 inch tube electric bicycle, bike, motorcycle, BOB 3-wheeler gear jogging stroller and most kids bikes; Like RoyalBaby, Joystar, Dynacraf and Revolution SE/Pro/Flex/SU/Ironman Heavy Duty Replacement Inner Tube: YeYouc 16x2.125 inner tube are made from premium, heavy-duty butyl rubber, they are also made 4X thicker adds to more stretch, shock absorption, impact and puncture resistance for a smoother ride Better Air Tightness: Heavy-Duty 16x2.125 bike tube made from butyl rubber, fitted with CR202L-A60 angled valve stem, ensuring straightforward installation and offer excellent sealing and air retention Package Includes: 2*16x1.75/2.125 tire tubes and 2 valve caps; Tips: Before installing, check to see if the inner tubes are completely sealed by putting them in water, if there are any bubbles, they are already damaged; If there are any quality or other issues with the products, Please feel free to contact us Heavy Duty 16x2.125 Thicker 40% Butyl Inner Tube, 16 Inch Bike Tube with CR202 Bent Valve Stem