Disposable hand warmer owder hot pack (hand warmer) with iron powder inside: It is disposable hand warmer which not be reused. The outside is nonwoven fabric, and 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 to warm fingers, hands or feet.