It is ideal for outdoor activity in winter or cold condition such as camping,mountaineering even break down on a high-way Body warmer:It is ideal for outdoor activity in winter or cold condition such as camping,mountaineering even your car break down on a high-way when suffering a terrible storm.It can provide 20 hours continous and steady warmth.It is very easy to use,just open the package and take it out,a few minutes later,it get to warm.You can put it in the pocket or sleeping bag