Detailed Product Description adhesive toe warmer/pain relief foot warmer material: iron powder,salt etc.warmer : up 5hours It is disposable hand warmer which not be reused. inside it is some iron powder, salt, activated carbon, water etc. It will warm up over 5-10minutes later after opening the outer polybag. This kind of hot packs (hand warmer) can be put into your cloth pockets, gloves, shoes ...