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Zpacks Classic 20° 900 Fill Power Down

rated 3.5 of 5 stars
photo: Zpacks Classic 20° 900 Fill Power Down 3-season down sleeping bag
Version reviewed: Long

This is an ultralight three-season sleeping bag (20 oz total). It works great during warmer nights unzipped and open as a quilt. It can be zipped up for colder nights. Zipped up, the fit is expectedly tight. These 900 fill bags come at a premium price.


  • Ultra lightweight
  • Fairly accurately rated
  • Did I mention ultralight weight?


  • Not as compressible as expected
  • Some feathers coming out already
  • Expensive

This review is about my Zpacks ultralight 900 Fill Power Goose Down Sleeping Bag - 20 deg Long.

I have only used this for one summer/fall season (about 6-7 outings).

When reviewing sleeping bags it always seems appropriate to note whether one is a "warm" sleeper" or a "cold sleeper". I am usually a warm sleeper except under conditions of high humidity. Then I am definitely a cold sleeper. This is one reason I no longer use a small ultralight tent, but that is another story.

The first thing you notice with this bag is it's incredibly light. It has no hood, like most mummy bags do. It is listed as 20 oz total. For most of the nights I used this temperatures did not get anywhere near down to the 20 degree rating, buy I got the 20-degree bag so that during the summer I could use it as a quilt just draped over me. For that, it worked fine—one hardly notices it on you.

During the colder nights of fall, I did have to zip it all the way up and wear a hat. I am guessing that the coldest night I had this year was around 25°. I was warm enough, although my feet were starting to feel a bit cool. I am not sure if I would have been totally warm at the listed 20 degrees spec. (how often are these correct, anyway?).  Note the trim of the bag—it's purposefully tight.

Here is a photo of the bag inside out to highlight the different construction of the down baffles.

The second thing you notice about this bag is it's pretty tight when fully zipped—tighter than any mummy bag I have had. This is the tradeoff for the light weight, and I am OK with it. The ribbing from mid-calf of the leg to the end is circular around the feet/legs, while the ribbing from mid-calf to the shoulders is lengthwise (90 deg different). I am not sure why that is, maybe to keep the down from shifting?

The specs on the Zpacks website lists a total weight of 20 oz and a packed size of 6 x 12 inches. I have weighed mine on my kitchen scale I get 1lb, 5.4 oz = 19.4 oz.

They give you a cuben fiber, water proof stuff sack. It's a little bigger than the specs. Depending on how much you squish it down, it runs 13-14 inches by around 7 x 6 oval. I was a little diappointed in the size.

bag1.jpgI was hoping "900 down" might squish down to the size of a 1-liter Nalgene bottle. Space is a premium in my ULA Circuit pack, more so than weight. However, it is certainly smaller than my other "normal" mummies.

The zipper is smaller than on my other bags—something I was a bit concerned about (sticking), but it has functioned just fine so far. There is no baffle tube along the zipper. One is supposed to lay on top of the zipper, so the small guage of the zipper helps in that. This makes it a bit more awkward to get out, but not enough of a hassle to really warrant a comment. The down seems to loft just fine so far—the magic of 900 fill power down, I guess.

As far as quality of construction goes, I think it is adequate (at this point). I have noticed a few feathers have poked through the "high quality ventum ripstop nylon with durable water repellent", but I think this is to be expected. I will review it again in a couple more years and see how it has held up.

These ultralight bags come at a premium price, that's for sure. Is it worth it? I have been trying to ligten my pack and have looked at all components. When I looked at $/onces saved, this sleeping bag made more sense thatn other comonents, so for me it is worth it. I gave it 3 and a half stars. I deducted half a star for the price.

Source: bought it new
Price Paid: $325 "bargain bin"

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Price MSRP: $359.00
Reviewers Paid: $325.00
Temp Rating 20°F / -7°C
Product Details from Zpacks »

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