An old idea to keep your hands warm

There was an earlier forum about a safe way to keep warm in a tent on a cold day and someone mentioned a metho heater. It reminded me of the pocket warmer my uncle gave me years ago. No idea how old it is. It is a flask that you fill with metho. You place the lid / wick on the flask, light it, put on the wick cover, place it in the bag and put it in your pocket. Never been game to put it in my pocket but I have held it in my hands and it works a treat. Used it a few ties ( in Canberra ) and had to knock back a lot of requests to borrow it. To be honest, I had my doubts I would get it back. It is about the same length and width f a computer mouse.

I just thought I'd share it. Don't know if anyone else has seen one. An ingenious old invention I intend to keep handy while travelling in winter.