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Big Agnes Blackburn UL Sleeping Bag: 0F Down


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Blackburn UL 0 Degree Down Sleeping Bag

Minimizing weight and space on gear-intensive trips is important, but so is not getting frostbite in the middle of the night. Take care of both problems with the Big Agnes Blackburn UL 0 Degree Down Sleeping Bag. Whether you're backpacking through high-altitude ranges in summer or going on a ski touring hut trip, the Blackburn UL is the ideal way to stay warm without tacking on too much extra bulk.

Down insulation keeps you comfortable through below-freezing temperatures while making the bag lightweight and highly compressible. This down is treated with DownTek to protect it from loft-compromising moisture. Just to be safe, the soft and smooth ripstop fabric is treated with a DWR coating as well to repel any wayward drips and drops. A full-length pad sleeve keeps your sleeping pad from shifting throughout the night, and an integrated pillow pocket keeps your camp pillow in place. You can even stuff it with spare layers when you really want to go minimalist. The Free Range hood and No-Draft collar, wedge, and zipper prevent cold air from slipping in through the cracks. Plus, the vaulted, tapered footbox gives your toes room to wiggle without creating large cold air pockets.

  • An ultralight sleeping bag for your cold weather backpacking trips
  • Lofty down insulation provides a superior warmth-to-weight ratio
  • Water-repellent down retains its heat-trapping loft in wet weather
  • Face fabric also repels light moisture to ensure dry comfort
  • Streamlined rectangular silhouette increases thermal efficiency
  • Free Range Hood offers freedom to easily lift and turn your head
  • Pillow barn keeps your pillow or extra layers tucked in
  • Big Agnes uses its Rock Mountain home as design inspiration
  • Item #BAG00ES

[shell] nylon rip-stop, [lining] nylon taffeta
850-fill DownTek
left or right
Max User Height
[short] 5ft 5in, [regular] 5ft 10in, [long] 6ft 6in
Shoulder Circumference
[short] 63in, [regular] 69in, [long] 72in
Hip Circumference
[short] 56.5in, [regular] 60in, [long] 63in
Foot Circumference
[short] 43in, [regular] 49in, [long] 52in
Bag Length
[short], [regular], [long]
Pad Retainer
[short] 25 x 66in, [regular] 25 x 72in, [long] 25 x 78in
Fill Weight
[short] 22oz, [regular] 24oz, [long] 26oz
Stuff Sack
Stuff Size
9 x 20in
Claimed Weight
[short] 2lb 2oz, [regular] 2lb 6oz, [long] 2lb 10oz
Recommended Use
backpacking, winter camping
Manufacturer Warranty

Tech Specs

What do you think about this product?


>Rating: 5

Oh, Isaac, you missed the boat!

I've used it several times

Isaac above is right, you must use an insulated pad with this bag to reap the benefit, but what a phenomenal benefit you will have. I understand Isaac's disappointment with the bag when it arrived and he realized that it's constructed to be as efficient and light weight as possible, that you absolutely must commit to utilizing the integrated system of an insulated (insulated air mattress is perfection with this system) pad inserted into the bottom sleeve engineered into this bag. If you go with the entire system (you don't even have to use Big Agnes pad), I guarantee you will have the coziest, most comfortable outdoor sleep you have ever had! Frustration with unmet expectation that was unintentionally off base is not a reason to rate a five star sleeping bag with a one star. The rating was misleading, but I feel for Isaac. Ike, hold in your pride a little, go ahead and purchase the insulated air mattress for this well designed and constructed bag and enjoy a warm five star sleeping experience!

In my experience, using a quilt style setup or mummy bag that doesn't have the insulation underneath does not work well with hammocks or cots. I spent the last two nights shivering in a 0 degree bag at temps in the 30's because it did not have insulation on the bottom. And yes, I was using an insulated air pad AND a closed cell foam pad. But because I was on a cot my heat was robbed from underneath me. From experience on other cold nights, I would have been warmer in my old 20 degree full mummy bag.

>Rating: 1

Will not work without the insulated pad

I returned this product before using it

There is an 8"-12" strip at the bottom-center of the bag that is completely uninsulated for ~80% of its length. This bag will NOT hold to it's temperature rating without the insulated pad (in a hammock, for example). That may well be exactly what the manufacturer intended, which is fine, but 1) I was led to believe otherwise in the Q&A, and 2) it would be most helpful if that was made clear in the product description.

You are a dumb shit. Every one knows you need apad with big agness. The only problems I’ve had with them is their zippers. Always snagging. Frustrating. And go with sea to summit pad


UL Down System Bag With Flex Pad Sleeve

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.


Would this work with just a foam pad or do you need a big inflatable to seal up the gaps?

Hi Anders, That is a good question. This sleeping bag would technically work with a foam pad, but you will definitely have some extra fabric. Depending how long your foam pad is, it should stay in place as it'll stretch it but not enough to 'fill' the extra.


What size Liter stuff sack will this fit into for backpacking? I had plenty of room in a 20L drysack for my 20degree Big Agnes on the AT, but am getting a zero degree bag for my PCT hike. I want to get the drysack while it is on sale. I HATE having a wet bag.

Hi there, With the dimensions this says stuffs down to 9"x20". Taking a look through a few dry sacks, I would recommend get a 25l dry sack, but it should roll up more the more you squeeze the air out.


Will this system work with pads that are not rectangle? like the thermarest neo air pad? And is it down filled on the bottom of the bag or does it rely on the pad for insulation?

Hi David, This bag will work best with a rectangular pad but as long as the pad is no more than 20" wide it should be okay. As for the bottom, Big Agnes system provides the insulation for about 3-5" into the bottom of the the bag and then it's just the pad sleeve, so it primarily relies on the pad for insulation.


Is the pad necessary? Would the temp rating hold true without it in a hammock?

Hey Isaac, Thanks for asking this great question. If you are hammock camping I would definitely suggest even a thin lining. It will be cold! Pads are usually a good idea to keep you insulated. The temperature rating will hold true, but it will get chilly at night.