Hand warmer warms your hands when activated, heating you up immediately. It can be used in both open and closed spaces to warm your hands. To activate it, all you need to do is push the metal plate and wait for it warm you up. It will remain warm for about 30 minutes. To re-use it, simply put the hand warmer without the outer coating in a cloth inside a pot of boiling water for about 5 - 10 minutes, leave it to boil until the content becomes liquid again.