Do you want something for hiking/backpacking or something to carry in your car emergency kit? For the car, I have a regular heavy-duty Space Blanket folded in half, then completely duct taped up the edge for form a bivy bag. I then fold this up as tightly as possible into a small roll and wrap it with a bunch of paracord (can't remember how exactly much cord, but it's a significant length). I can always cut or peel off the duct tape "seam" to unfold the Space Blanket to use as a tarp in combination with the paracord. This wouldn't work for hiking/backpacking because it is bulky and heavy. But for a car kit - it's what I use (technically, I've never had to "use" it, but I "carry" it in the car kit for "potential use" in an emergency).