The hinged extra large heat patches deliver 8 hours of soothing heat and provide targeted, temporary warming relief from muscular and joint aches and pains. Just open the sachet , unfold the heat patch and apply directly to the skin over the painful area where the heat will increase blood circulation, decrease stiffness and relax sore muscles. Fragrance free, non medicinal and with a thin discreet design, they are ideal to use anywhere.