Duro Bicycle Tube 20 x 1.3/8 F/V 48mm (37-451)

High-pressure inner tube designed for compact and folding bike wheels. Fits 20-inch rims with 1 3/8-inch tyre width (37-451 ETRTO sizing). Features a 48mm Presta valve for reliable inflation control and compatibility with floor pumps and portable inflators. Durable rubber construction handles daily commuting and recreational riding. Essential replacement for maintaining tyre performance and ride quality on smaller-wheeled bikes.