Replace your worn out or flat bike tube with the Nishiki(R) Presta Valve 27.5'' 1.90-2.125 Bike Tube. This bike tube is designed to fit 27.5" tires with a width range of 1.90-2.125 and features a Presta valve that is 33mm in length. You'll be prepared for the rocky trails with the Nishiki(R) Presta Valve 27.5'' 1.90-2.125 Bike Tube. FEATURES: Replacement bike tube Best for mountain bikes Fits 27.5" tires with a width range of 1.90-2.125 Valve type: Presta Valve length: 33mm Tube width: 42mm Tube thickness: .95mm