The mylar kept me dry through a surprise rainstorm and blocked the wind completely. Shook it out and it folded back into the sack fine, though the crinkle noise takes some getting used to.
Timothy H.★★★★★
Took this on a cold, windy overnight hike and it kept me surprisingly warm—the mylar really does bounce heat back at you. It's thin and crinkly, but it packs down to nothing and weighs almost nothing in my pack.
Brian V.★★★★☆
Kept one in my car's glovebox all winter and it's surprisingly compact for how much warmth the mylar traps. Only gripe is the material rustles loudly when you shift around, but for an emergency bag that's a fair trade.