Big Agnes Star Fire UL 20˚Ultralight Down Fill Sleeping Bag

$499.95 - $529.95
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Big Agnes Star Fire UL 20˚Ultralight Down Fill Sleeping Bag


Technical, ultralight down fill traditional mummy bags designed to excel in all conditions


These technical, ultralight bags are designed for adventures where every ounce counts, each nook and cranny in your pack is accounted for, and you depend on the performance of your sleeping bag like you would a harness, helmet, or beacon. The "Fly Creek of sleeping bags," our Star Fire UL series features the ultimate 850 fill power DownTek™ water-repellent down, and are built with a superlight, high-tear strength shell that also protects the inside footbox. Body-mapped baffle construction optimizes thermal efficiency creating the lightest, highly compressible bag for your most remote of overnight adventures.

Specs + Sizing

Bag Weight Small: 1lb 12oz / 794g / Regular: 1lb 15oz / 879g / Long: 2lb 2oz / 964g
Fill Weight Small: 15oz / 425g / Regular: 17oz / 482g / Long: 19oz / 539g
Compressed Bag Size Small: 6.5" x 7" / 17 x 18cm / Regular: 6.5" x 7.5" / 17 x 19cm / Long: 7" x 7.5" / 18 x 19cm
Stuff Sack Size Small: 7.5" x 15" / 19 x 38cm / Regular: 7.5" x 15" / 19 x 38cm / Long: 8" x 17.5" / 20 x 45cm
Sleeping Bag Type Traditional Mummy Bags



Ultralight down mummy bags that feature 850 fill power 

DownTek™ down and a Pertex® shell to create our most compressible, technical bags

Traditional mummy shape allows for lightweight and increased thermal value

Body mapped baffle construction optimizes thermal efficiency

3-D anti-snag draft tube prevents heat loss along the zipper

Vertically structured sidewalls integrating contoured baffles trap heat closer to the body

Contoured hood baffles cradle the head for a more comfortable fit

Oversized interior anti-draft collar 

Ergonomic foot-box construction provides more loft and warmth 

Low-profile cordlock lets you un-cinch the hood with one hand

Insulated tube along upper hood opening seals out drafts when cinched 

Minimal zipper minimizes weight and reduces cold spots

40"/102cm YKK #5 anti-snag zipper for a smooth, quick zip 

Zipper Garage

Interior fabric loops for sleeping bag liners

Streamlined exterior loops for hang drying or storage

Storage sack & stuff sack included 


Construction + Materials

Shell and lining are Pertex® Quantum nylon rip-stop 

100% recycled Pertex® Quantum uses a tightly woven structure made from incredibly fine yarns, making a light and soft fabric that allows insulation to fully loft and maximize thermal efficiency

850 fill DownTek™ repels water while maintaining insulating value - bluesign® Certified PFOA and PFOS free water repellent chemistry 

Insotect Flow™ vertical baffles contour to your body to provide a more comfortable fit and keep you warmer