Big Agnes

Big Agnes Zirkel SL Sleeping Bag: 20 Degree Down

Big Agnes designed its Divide SL Series sleeping bags for campers and backpackers looking to keep things lighter than a feather and warmer than a Saharan summer. If you're being picky, the Zirkel SL 20 Degree Down Sleeping Bag isn't technically lighter than a feather—it weighs a whole 2.3 pounds, and is insulated by a toasty mess of water-resistant DownTek 800-fill down—but it will keep you warm down to 20 degrees, making in a perfect option for for spring, fall, and mild winter camping and backpacking. In contrast to traditional horizontal baffles, the Zirkel features a vertical baffle system for a better fit, and it employs Insotect Flow construction, which features staggered "gates" inside of the baffles to prevent the down from migrating and leaving you to deal with cold spots.

Big Agnes used lightweight but tough Pertex Quantum nylon on the inside and outside of the bag for softness and durability, included a draft-proof collar, wedge, and zipper to keep your warm air in and chills at bay, and included a snug hood that helps you sleep comfortably while making sure your pillow doesn't wander away from your head in the middle of the night. It's important to note that the Zirkel uses Big Agnes' BA System, which forgoes insulation on the bottom of the bag in favor of a pad sleeve, which means you'll need a 20in pad to provide insulation from the ground. This reduces the weight of the bag without compromising warmth, assuming you were going to bring a sleeping pad with you anyway, so you'll trim ounces without feeling even a degree colder.