Tubes Cycling, Outdoor Recreation, Sports & Outdoors, Tires & Tubes, Zol Zol Bicycle Bike Inner Tube 20″ x1 3/8 Presta Valve 48mm Valve Review by Coyotea August 29, 2018 No Comments Made out of butyl construction Weight 200 grams Presta Valve/French Valve stem 48 mm long Fits most modern Kids Bikes and BMX and Recumbent Bikes fits all 20″bike tires Zol road tubes are made to meet training and racing standards