Vinylon F is the name of the hard-wearing fabric that has contributed to Kånken's popularity over the years. While being a synthetic material – it is made of a fibre called polyvinyl alcohol – it has certain properties that are otherwise mostly found in natural materials.
The fabrics used in rucksacks normally require a coating, such as polyurethane (PU) or silicone, in order to be water resistant. The vinylon fibre, on the other hand, behaves like a natural material and swells when it becomes damp.
This, in combination with its excellent durability, is one of the reasons why Vinylon F has been fashionable at Kånken since the end of the 1970s.