Teravail Standard Tube - 26 x 2.4 - 2.8 40mm Presta ValveTeravail Standard Tube 26 x 2. 4 2. 8 40mm Presta Valve. The Teravail Standard Presta Valve tubes feature our widest variety of tube sizes and valve lengths with a proven record of high quality control and consistent availability. 0. 9mm wall thickness Removable Presta valve core Teravail Standard packaging features environmentally friendly soy ink printing on recycled cardboard Master Cartons of Standard tubes contain a total of fifty tubes: five