It is made up of permanent magnets the bio-composite heat-chip Moxibustion consists of tourmaline Nano-functional ceramic powder and a special heat sensitive materials also with the application of ignipuncture theory in traditional Chinese medicine - It can apply to all kinds of joint pain help expel wind and clear away cold warm and activate meridian promote blood circulation to arrest pain etc. Product Type: Ankle Support Size: Universal (fits virtually all male or female ankles) Keep warm on your Ankle Support Pain Relief Nice gift for parents family lover and yourself. Fits male or female ankles Use everyday or as needed. Comfortable to wear