Never seen one of these, but my dad used to have charcoal hand warmers similar to this: https://www.amazon.co.uk/Pocket-Hand-warmer-charcoal-including/dp/B002V

Never seen one of these, but my dad used to have charcoal hand warmers similar to this: https://www.amazon.co.uk/Pocket-Hand-warmer-charcoal-including/dp/B002VKO19S https://www.amazon.co.uk/Pocket-Hand-warmer-charcoal-includi... We used to take them to football matches but eventually they became the sort of thing they'd confiscate cos fire and idiots don't mix.