PrimaCare Mylar Thermal Heat Emergency Blankets (20 Pack)

I didn't use these for what they were advertise for. They look like tinfoil but they are soft and pliable but strong. The don't crunch up like tinfoil. I did put a few in the car in case of emergency. Living in a desert I worry about the car breaking down in 107 degree heat. They reflect the sun really well. These things surprised me. If you put them over a window you can see out but no one can see in during the day. Just the opposite at night when it is dark out side and light inside. I live in a high desert. I have large windows in my hallway. I just tacked them over the window and still have plenty of light but it blocks the heavy sunlight. I ended up a hero for giving some to my son who used them to block out light behind his curtains. He can open curtains and see out which makes him feel less boxed in. Also saves on sun damage to curtains. Highly recommend having some around.

They work great as window insulation. I stretched them out as curtains and secure the edges. They let light in but not heat nor cold. They are great that in the daytime, I can see out but outsiders can't see in.