Once the metal disk in a Wonder Warmer® is pressed, the liquid in the pad crystallizes in a chemical reaction that is fascinating to watch and generates heat for 30 minutes to over 2 hours depending on the pad’s size, construction, and insulation, and the temperature outside.
Activation
Crystallization and heating
Ready for use
The pad is “recharged” by boiling it for approx. 5 - 12 minutes (i.e. Until all of the crystals melt back into their original liquid state). If all of the crystals are not melted, the pad will activate on its own as it cools.
The activation and recharging of a pad can be repeated a virtually unlimited number of times, provided the pad's pouch is not damaged. Although the pad will not work if the pouch is damaged, its contents pose no threat as they are common non-toxic food additives.
