You're visiting Alaska in September because you came for the autumn foliage, the blueberry bushes turned magenta, the golden aspen, the blood red leaves of bear berry. You came for the midnight show. You also know you might wake up to frost in the morning. That's quite alright because the Sierra Designs Nitro UL 800 DriDown 0 Degree Sleeping Bag will give you a good night's rest, keeping you warm even if the muskeg gets your gear a little wet. Packed with lofty down, the soft folds of the Nitro UL 800 offer comfy levels of warmth at temperatures well below freezing. The bag is lightweight for long trips into the Alaskan wilderness, and it packs down small. The Dridown doesn't mind if things get damp--treated by Sierra Designs to be hydrophobic, these feathers keep you warm rain or shine. A five-inch baffle design also means those feathers aren't moving around as much, keeping you warmer. If things do get a little stuffy at night, you can just bend your knees and the foot vent pops open, letting in a cool draft. When your partner wakes you up at two in the morning because there's a wild aurora borealis display, the anti-snag zipper tracks means you can be out of bed in a jiffy, and back in just as easily.