Big Agnes divide UL bags combine lightweight materials with high performance design: save weight without sacrificing warmth.

The Zirkel SL 20-degree mummy sleeping bag from Big Agnes is designed for weight conscious adventurers who don't want to sacrifice a good night's sleep. With lightweight and warm 800-fill down and a 20-degree temperature rating, the Zirkel offers versatility for multi-season use. The Zirkel's mummy shape offers the best possible interior warmth and weight savings, but the most exciting aspect of this bag is its smart, integrated half-pad sleeve. In exchange for insulation on the bottom of the bag, this sleeve anchors you to the pad and uses the pad as insulation, so that you can move freely as you sleep without ending up off the pad or at the bottom of your tent. Additional details that set the Zirkel apart include a sturdy yet soft water resistant shell, a high-thread count interior liner, a built-in pillow pocket for use with a fleece or a real pillow, and the ability to mate the bag with a like-sized Big Agnes sleeping bag. The Zirkel is also detailed with interior fabric loops for sleeping bag liners and no-draft seals. The bag comes with a recycled mesh storage sack and a nylon stuff sack included and carries a lifetime warranty against material and manufacturing defects. Half Pad Integrated Bag and Pad System:
The Integrated Bag and Pad System replaces the sleeping bag's bottom insulation with a sleeve that holds your pad. Recognizing that when sleeping bag fill is compressed under your body, it loses most of its ability to insulate, the pad sleeve securely attaches you to the pad from the hips up--and allows the sleeping pad to provide more effective insulation. The half pad sleeve has an adjustable strap that holds any 20-inch wide rectangular or mummy shaped pad. The system keeps you anchored to the pad from the hips up while allowing full freedom of movement for your legs. This secure foundation keeps you on the pad and off the cold ground all night and the system also results in lower sleeping bag weight and smaller packed size.

The half pad sleeve allows you to secure any 20-inch wide pad to your bag, so that you never wake up on the cold ground again.

Additional Features:Mummy shape decreases weight and packed size Built in pillow pocket holds a fleece or Big Agnes pillow Interior fabric loops for sleeping bag liners 60-inch YKK #5 zipper mates together with any Big Agnes left and right zip bags with the same size zipper No-draft collar seals around neck to keep cold air from sneaking in No-draft wedge insulates the connection between the bag and the pad No-draft zipper tube insulates along the length of the zipper Shell Fabric: Pertex Quantum rip-stop nylon. Featherweight, high thread-count fabric that is soft as silk with a small packing volume. WR surface treatment to repel water. Recycled mesh storage sack and nylon stuff sack included Lifetime warranty against material and manufacturing defects Specifications:Fit: up to 5 feet, 10 inches (regular); up to 6 feet, 6 inches (long) Bag Weight: 2 pounds, 4 ounces (regular); 2 pounds, 9 ounces (long) Fill Type: 800 fill goose down Fill Weight: 15.5 ounces (regular); 16.5 ounces (long) Shoulder Girth: 67.5 inches (regular); 72.5 inches (long) Hip Girth: 64 inches (regular); 69 inches (long) Foot Girth: 43 inches (regular); 44 inches (long) Stuff Sack Size: 7.5 by 15 inches Compressed Size: 7 by 6 inches (regular); 7 by 6.5 inches (long) Pad Size: any 20-inch wide pad