http://www.mustangsurvival.com/military/hypothermia?country=25 These are really great suits to keep warm. Luckily I found some of the olive drab ones at a yard sale for only $20 each but you can find some on eBay. You could always get a white Tyvek suit to wear over it if you live in an area where there is snow. I know we will NOT freeze just by having these suits!!! These will keep you warm if you can't build a fire or don't have or run out of propane/kerosene, or generator. This is a good investment because if you use other means of keeping warm (a fire which people can see or smell) people will be drawn to the comfort of the heat you have if SHTF this winter.