If traditional mummy bags make you feel straitjacketed, you'll get relief with this stretchy bag. MontBell sews this sack with elasticized thread and extra shell material, so you can bend your knees, sit comfortably with your legs crossed, and generally toss and turn uninhibitedly all night long. And when you lie still, the elastic nature of the bag eliminates dead space so you don't have to heat excess air. With 800-fill down, it still packs into a stuffsack the size of a loaf of bread. 25ºF, 1.7 lbs; montbell.comBonus: Not six feet tall? Use the cinch cord at the foot to seal off the last baffle and fine-tune the fit and increase thermal efficiency.Bummer: The delicate 15-denier shell material saves weight, but it's not made for throwing down on granite slabs.