The new hi tech way to keep cool that costs nothing to run these medical grade pads are filled with a harmless gel that delivers an amazing cooling effect when in contact with your body the cooling effect is activated every time you move and is a lovely dry coolness not wet or sweaty you dont need to refrigerate or freeze the pads first unless you want to be really icy cool great for hot head headaches hot feet hot flushes sunburn or just to cool down in hot weather or over heat