I've got an old school puncture repair kit, the type with glue and patches.
As well as the sandpaper, patches, 'vulcanizing fluid' and instructions, there is a 2.5cm long, 3mm wide, beige rubber tube.
What's it for?
(it doesn't seem to appear in the pictorial instructions)
It is the Dunlop valve, it was used a lot in Holland, UK, etc.
You can see it in action here:
But currently it is replace by the Blitz:
They are for old "Dunlop" or "Woods" valves, that were halfway in size between a presta & schrader valve. Just inside the cap (that you could screw off) was the rubber tube that acted as the valve. If it split or broke (usually when the rubber perished) you could replace it and be on your way again.
We have Dunlop valves described in the Terminology Index, and you can find more out at Wikipedia.
Modern versions of this valve use a different method to keep the air in, a small ball in the valve and a rubber ring that does not stop the air flowing in. These hardly ever fail in use but can get stuck if not pumped in a long time.
Sounds like extra material for the type of valves that aren't Presta- and not "car-like"- (Schrader) either - Dunlop valves. They use a short piece of rubber tube to seal.
