It's not a bottle warmer!
In the summer when it gets really hot I like to carry ice cold water around with me everywhere I go. The problem is that the bottle sweats and drips inside my bag or onto my hands and clothes. So I've created this "patent" (not registered) which completely solves the problem. It can be put inside a bag with books and paperwork or it can be carried on it's own instead of carrying the bottle in a nylon bag (which is ugly).
Ideal yarn is cotton - needle size around 5 mm (7/8).
May be somebody on this forum can think of a good name for it.
It has been a real "hit" amongst my friends and I can't seem to be knitting them fast enough.