I've mentioned this stuff before, but I think I said it was Storm King window film- well it's Frost King. Same stuff you buy from GG or MLD. You can get it HD or Lowes for about $8. 84" x 110" plus a roll of 1/2" double sided tape that's good all sorts of projects. I can get two ground sheets out of it. Cut it with a hot knife for best results as it keeps the edge strong when it's melted. Super light and durable. A piece will fold up to size of a deck of cards. Great for putting on those nasty shelter floors. I keep mine in an outside pack pocket so I spread it out at break time if I want to stretch out.