Blackburn UL 0˚

Ultralight down fill Big Agnes System bags designed to excel in all conditions

The Blackburn UL 0 is one of our most technically designed Big Agnes System bags, using our Flex Pad Sleeve design, a very durable nylon ripstop shell fabric, and super cozy 850 fill power DownTek™ water repellent insulation. This bag combines ultralight versatility with a long line of packable creature comforts. Whether you’re a 3/4 length-pad carrying, fast-fly tent gram counter, or just gearing up for a cold weather hut trip where weight and packed size is important, this is the go-to bag for you.
$399.96 to $519.95
100% Guarantee


Our top priority is to provide customer service as stellar as the award-winning products we create. If one of our products does not perform to your satisfaction, contact our customer service team and we will help you find gear that fits your needs.

Specs + Sizing

Bag WeightSmall: 2lb 6oz / 1.08kg / Regular: 2lb 10oz / 1.19kg / Long: 2lb 14oz / 1.30kg
Fill WeightSmall: 22oz / 624g / Regular: 24oz / 680g / Long: 26oz / 737g
Compressed Bag SizeSmall: 5.5" x 6.5" / 14 x 17 cm / Regular: 6.5" x 7.5" / 17 x 19cm / Long: 7.5" x 8.5" / 19 x 22cm
Stuff Sack SizeSmall: L 9" x 20" / L 23 x 51cm / Regular: L 9" x 20" / L 23 x 51cm / Long: L 9" x 20" / L 23 x 51 cm


The lightest Big Agnes System bags offer technical, roomy sleeping spaces for those who aren't willing to sacrifice comfort or compressibility 

Streamlined silhouette for increased thermal efficiency 

Flex Pad Sleeve features stretch construction that accommodates multiple pad widths, and easily connects your bag to your pad  

Small, Regular and Long bags fit 20" - 25" wide pads

Free Range Hood gives you the freedom to lift your head. Jacket-style hood opening contours to the shape of your face for a comfortable, snug fit

Rectangular shaped bag

DownTek™ - a water repellent down that uses a PFC-Free, bluesign™ approved chemistry.

Anti-snag zipper for a smooth, quick zip 

Zipper Garage 

Mate together left and right zip bags

No-draft collar, no-draft wedge, no-draft zipper

Interior fabric loops for sleeping bag liners

Exterior loops for hang drying or storage

Mesh storage sack & polyester ripstop stuff sack

Small: 60" / 152cm YKK #5 anti-snag locking zipper

Regular: 65" / 165cm YKK #5 anti-snag locking zipper

Long: 70" / 178cm YKK #5 anti-snag locking zipper

Construction + Materials

Nylon ripstop shell fabric with a water repellent finish 

Nylon taffeta lining 

Insotect Flow™ construction

850 fill DownTek™ - a water repellent down that uses a PFC-Free, bluesign™ approved chemistry.

Here’s what other people think.

What’s in a Name?

The Blackburn mine was a dominant and fruitful gold mine located in the Hahns Peak region of the Yampa Valley. Paired with the El Capitan and Ben Harrison Placers mines, the discovery of gold in the area in 1862 established the Hahns Peak region as part of Colorado's gold rush.