Originally developed for NASA to protect their astronauts & equipment from solar radiation & the extreme temperatures of space – now we can all enjoy the benefits of this wondrous Space Age technology! Its technical name is ' Mylar' & it may look like a sheet of wafer thin tin foil, but this high-density material maintains up to 90% of your body heat once it's wrapped around you. Science! Kinda crazy to think that these Astronaut Blankets were used on the Gemini & Apollo Missions & now you can use them if you're feeling a bit nippy on a camping trip!