Cura-heat Arthritis Refill packs help to deliver deep, comforting heat for up to 8 hours. It helps to deliver heat therapy in an easy to use format and works by increasing blood flow to the source of pain to relieve the pain and aches associated with arthritis in the joint area. Unique design This patch has a thin discreet, ready-to-use design, making it ideal to use anywhere. Also, it is portable and can be carried anywhere. This product is fragrance-free and non-medicinal. How it works It contains the ingredients such as iron, activated carbon and water, which oxidise and produce heat when it comes into contact with the oxygen in the air, to provide constant, comforting heat.