Our hand warmer kit contains iron powder, wood powder and activated carbon. It can be good material, fast heating, no powder leakage, no iron powder. The way to use it is simple: 1. First, wash your hands with disinfectant and warm water. 2. Unwrap the hand warmer and place it in your hand to let it warm up naturally. 3. Cover your hand with the hand warmer and your hand will slowly warm up for a long time. Suitable for people who are afraid of cold/abdominal discomfort. Mini size, fits in bags and pockets.