Air-activated hand warmers contain cellulose, iron, water, activated carbon, vermiculite (water reservoir) and salt.
This produces heat from the exothermic oxidation of iron when exposed to air.
Having seen this advert a number of times and just listening to it on the radio, what is the point of hot hands?
Haven’t gloves and mittens been doing that for years?
And I’m sure they don’t stop working after a few hours.