This specially-shaped, reusable heat pad provides instant heat with just one click to activate.Designed to fit comfortably around your neck and shoulders this instant heat pad is ideal for targeting aches and pains, improving poor circulation and soothing injuries. When you click and bend the metal disc inside the pad, it heats the whole Heat Pad in seconds, with no other power source required. To reuse the heat pad, heat in gently simmering water (do not boil) to melt the crystals back to the original liquid state, ready for your next click!