The uses for a survival blanket are endless. It will reflect 90% of your body heat back to you. It is waterproof and is cheap enough to get a few and throw one in a survival kit, one for the car, and one for fun. You can use it as a tarp to construct shelter or cut a section off and use it as a water container. When the aliens attack, use one to make a hat and protect your loved ones from alien gamma-ray mind-control devices.
But seriously, in a situation where you might be stranded in cold and wet weather, a survival blanket could save your life or at least keep you comfortable while you wait for help.
This particular survival blanket measures 84 x 52 inches.