Cathy 20 x 1.35 (406) Bicycle Inner Tube SV (Schrader valve)
Size: 20 x 1.35 inches
Butyl is a subsitute for latex. Most tyres are made of Butyl nowadays. Butyl can be a bit heavier than latex but less porous
Note: Important to note that 406 and 451 are both marked as 20" but they are different and not interchangeable
Confusing abbreviations used for denoting type of valve, but they mean all the same!
F / V or S / V for French valve or Presta valve
A / V for Schrader valve or Auto/ America Valve
Some tube companies use S / V to denote Schrader Valve.
If you want to know more about innner tube sizing, visit
Last Updated: mag 2016-10-03