The cups come with 2 heat pads that are inserted into pockets in the cups.
Very useful for skiing and winter sports, however, are also used as a fashion accessory.
Heating pads can also be used as hand warmers. COLORS MAY VARY
Pads instant heat generation are very safe and non toxic due to an innovative use of salt based on sodium acetate solution. On flexing the small metal disc that is inside the pad creates a reaction that produces the beginning of the crystallization of the solution. This reaction does the crystallization of all the liquid inside the pad and the result is the release of energy as heat. Gradually the heat pad is reduced, returning to its original solid state. The time it takes for this process depends on the type and size of the pad, however this process can be restarted by allowing the use of the pad over and over again for a long time. You only have to dip the pad in hot water and let stand, turning to a liquid, and ready for reuse.