Backpacking is all about versatility. If one piece of gear can serve as two, you’re saving weight and keeping your gear consolidated. Sierra Designs tackles the age-old backpacking problem: should I bring more layers for hanging out around camp, or go light and forgo the fireside conversation? As a cold-blooded backpacker, I typically carry an unnecessary amount of clothing so I can enjoy the evenings while still feeling my fingertips. But the Mobile Mummy offers an innovative solution.

Screen Shot 2016-07-12 at 9.47.16 PMFirst off, you’ll notice the innovative design. Sierra Designs took the conventional sleeping bag and just threw it out the window. Rather than making the customer commit to either a left or right zipper, the Mobile Mummy features a central two-way zipper that runs from hood to the foot box. Gone is the oversized drawstring hood, replaced by a jacket-like hood that actually fits your head. Small shoulder-height flaps allow you to easily fit your arms through the sides of the bag for mobility or to accommodate any sleeping position. Of course, the bag features 800-fill DriDown, making it a superb choice for temperate environments.

The Test

Melissa - Sleeping Bag Product Review-5I tested the bag at both 5300 feet and 1500 feet, in two very different conditions. I camped at 1500 feet for several days with rainy nights and misty mornings to see if the bag would saturate. I toted the bag to a higher elevation at Pilchuck Lookout for the second test and used it to lounge around the lookout deck in the wind and rain. While the EN-rated 20 degree bag works exceptionally well in the colder temperatures and at high elevations (arms in or paired with a down jacket), the arm holes and two-way zip offer superior ventilation for warmer nights or lower elevations. Because of the hydrophobic DriDown fill, I wasn’t hesitant to walk around in the bag in dense fog and drizzling conditions. The bag remained dry and insulating, even after days in the Washington rain forest.


Screen Shot 2016-07-12 at 10.26.19 PMWhile most sleeping bags are engineered for back sleepers, the Mobile Mummy’s design accommodates any sleeping position. Slip your arms through the arm flaps or unzip the bottom of the two-way zipper to poke a leg out. The central zipper, fitted hood, and slightly slimmer hip and foot box means that the bag actually stays oriented to your body as you move during the night. I tested the bag with my arms both in and out, and found that the shoulder width (a roomy 3 inches wider than Sierra Design’s comparable mummy bag) easily accommodated my arms inside the bag. The ability to customize the bag to my desired sleeping position allowed me to get a more comfortable night’s sleep than in a standard mummy bag.


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The mobile mummy is versatile, arm holes allow the bag to be worn around the camp site. Photo by KPHorizons LLC

It’s not called the Mobile Mummy for nothing. The bag quickly converts from a sleeping bag to a warm garment to wear in the tent or around camp. Zip up the hood and slip your hands through the arm flaps. Simply unzip the bottom of the bag (I found that about 2 feet was just right for me) and secure the foot box using a pair of plastic toggles. There are toggle loops located 2 and 3 feet from the bottom of the bag, letting you customize how high the footbed is gathered. Note: the toggles did take some time to fasten at first. Now you’re ready to move! But after some tweaking and personalizing, the bag is surprisingly unrestricted. The arm holes make it much easier to move gear around the tent, or cook without leaving the comfort of your sleeping bag. On cold mornings it’s usually a challenge to leave your sleeping bag, but now you don’t have to.

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The two-way zipper and toggle cords allow you to open the bottom of the mobile mummy and hem the footbox up making the bag fit like a coat. Photo by KPHorizons LLC

What Are the Sacrifices?

I know you’re wondering it. With all the added features and versatility, what are we going to sacrifice? With a trail weight of 2 pounds, 7 ounces the Mobile Mummy 800 is actually 6 ounces lighter than Sierra Design’s 20-degree mummy equivalent. What about compression? The accompanying stuff sack is 15 X 8 inches, but I was able to easily compress the sleeping bag to 10 X 8 using a compression sack. Admittedly, not as compact as some competitors, but completely acceptable given the advantages. Insulation issues? I didn’t notice any drafts from the arm flaps, even as the temperature dipped below freezing.

Style? Well, I’ll leave that to the fashionistas.

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Can you jump for joy in your sleeping bag? Photo by KPHorizons LLC

I have to admit that I was skeptical at first about forgoing my mummy bag for this wildly unconventional sleeping bag. At just over $400 the Mobile Mummy 800 3-season bag is a bit of an investment, but let me tell you it’s worth it. A bag that doubles as a down garment is enough utility to warrant the price. It’s rare to find a 2-pound, 7-ounce 20-degree DriDown women’s bag in that price point — typically you either sacrifice weight, warmth or compressibility.

Women's Mobile Mummy 800 3-Season











  • Hydrophobic 800 Fill Duck DriDown
  • Two-Way Center Zipper
  • Arm & Leg Mobility
  • Fitted Hood
  • Trail Weight (2 lb 7 oz)


  • Toggles Difficult to Fasten

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