Originally Posted By: ironraven
The mylar is a low performer becuase it's just a thin layer of reflective material on the plastic- hold it up to your eye on a sunny day and you can see through it.


I don't have a space blanket handy at the moment, but I have one of those mylar bags that electronics are packaged in. Yup, you're right. Pointing it up at the sun, light does get through.

Thank goodness, I can still keep my mylar-lined hats around to keep the guys in the black helicopters from stealing my thoughts. Wait, maybe I've been wrong about it actually being good even for that purpose... shocked