This Large Rectangle Warmer is ideal for soothing aches and pains on the go. Simply click the metal disk and the liquid in the warming pouch crystallizes in a fun-to-watch chemical reaction that generates heat for up to an hour. When you’re done\ just boil the warming pouch until the crystals have melted and you’re ready for a click of the metal disk and a new round of mending warmth."
Reusable 100+ times. Pad will not work if the pouch is damaged. The contents pose no threat as they are common non-toxic food additives.