When was the last time you poured water on your down sleeping bag? Crazy, right? But with new DownTek technology, Big Agnes has created the Lithia Spring DownTek sleeping bag for women (the men’s equivalent is the Bellyache Mountain). It is supposed to give you all the benefits of down, without all the problems that wet down causes.

I have always been a synthetic bag user since I live here where it’s wet all the time. I just assumed that you had to give a down bag the same care as your grandmother’s crystal so that it would survive in the backcountry. Well the new age of down technology is here and this is how it held up.


I rolled it out in the snow and sat on it while I donned crampons. It was a 38 degree day and the snow was slushy. A regular down bag would have cried. The Lithia didn’t waver. The fabric is good at repelling water and snow and even though I rubbed a wet snowball into the fabric, it didn’t mat the down. I made sure it was nice and damp all over, then I stuffed it into its stuff sack and took it home and let it stay in there for two days. I thought this would allow the down to soak up moisture and begin to crush, but it didn’t. When I pulled it out, the fabric dried within a half hour and all the down was still fluffy. If you haven’t seen the demo on DownTek, check it out.


I love the fabric. Most down bags I’ve handled have an unsettling crunch to the fabric. This makes them loud to sleep in. The Lithia has not only great colors, but a soft, silky fabric that didn’t run or pull, even when I ran my ragged fingernails across it. The draw closures, zipper pulls and velcro closure are all well thought out. I am a pro at getting a sleeping bag zipper stuck on the fabric, but Big Agnes went to the trouble to make the zipper surround in a slightly stiffer fabric and that kept me from having any trouble with the zipper. I love the down collar that Big Agnesbuilt in. It does a decent job of locking out drafts, far more than a regular mummy bag so I didn’t have to wear my scarf or balaclava with this one.


It’s a good size. A women’s bag fit me, 5’6″, very comfortably and I’d bet even a 5’9″ person would do well in there (Big Agnes says even 5’10”). It’s cut wider in the hips, as most women’s bags are, and a bit narrower at the shoulders. For a 10 degree bag it packs down reasonably small, and a bit better than than my 10 degree synthetic bag. Big Agnes hasn’t decided if this is a 10 degree bag or a 15 degree bag though. The embroidery on mine says 10 degrees, while the online product description says 15. Nothing to lose sleep over. It’s plenty warm enough for all but your wildest alpine expeditions.

It needs to come with it’s own compression sack though. I had to rob another sleeping bag to see how well it compresses. It does better than any of the synthetic bags I’ve ever had. It was reasonably warm and since I usually sleep in men’s style sleeping bags, I did notice the extra warmth in the footbox.

Pacific Northwest backpackers don’t need to avoid down anymore! This bag is well built and uses technology and materials that are well suited for our wet environment.


  • Amazing down technology – really stays dry
  • Neck collar seals out drafts
  • No catch, no run fabric, smart zipper fabric
  • Left and right zip styles zip together (aww!)
  • Pretty colors


  • Needs a compression sack

Technical Details

Date available:

Manufacturer’s Website: Big Agnes Lithia Spring

MSRP: $379 (petite is $349)

Listed Weight: 3lb 2oz

Materials: Fill: 700 DownTek™ , Fabric:

Dimensions: At Shoulder 56″, at Hip 56″ at Foot 36″ (Petite is 2 inches smaller in all dimensions)

Size/Model tested: Women’s Regular (also available in petite for a touch less weight)

Colors Available: purple/gray

Fill Weight 29oz 31oz

Bag Weight 2lb 9oz 3lb 2oz

Stuff Sack Size M-8″x17.5″ M-8″x17.5″ Compressed

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