Heat...anywhere! Anytime! Simply flex the little metal disc, and they become hot instantly! Magic heat pad gives instant heat up to approximate 130 degree F/ 54 C when activated, and can be reused many times by following the instructions. It could be used outdoor. For physiotherapy, it works especially effective on muscle aching, back aching, cramps, arthritis pain, tenontodynia and etc. the heat pads are a novelty exciting useful health product and gadget.