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Mountain Hardwear
Phantom GORE-TEX Sleeping Bag: -40F Down

4.724137931034483 out of 5 stars
29 Reviews
$989.99 - $1,019.99
Color:Alpine Red



Why We Like The Phantom GORE-TEX Sleeping Bag

Designed for the nights adjacent to high-alpine summit bids and deep winter dawn patrols, the Phantom GORE-TEX Sleeping Bag defends us against brutal conditions. This bag features GORE-TEX WindStopper, which seals out the coldest winds and resists moisture to protect the insulation. Mountain Hardwear filled the Phantom with 850-fill goose down for effective, efficient insulation that clocks in at a surprisingly low weight. We appreciate the vertical sidewall baffles that maximize loft, and therefore warmth, while the winter mummy cut efficiently adds space for cold-weather gear storage and extra layers. A centered, half-length zipper makes sitting up and getting in and out a breeze, while an ergonomic draft collar works with the face gasket to ensure heat won't escape at vulnerable points.


  • Intense sleeping bag for brutal winter conditions
  • GORE-TEX Windstopper is wind-proof and water-resistant
  • 850-fill goose down is an extremely effective insulator
  • Ergonomic draft collar comfortably seals in heat
  • Spacious mummy shape for extra layers and gear storage
  • Rated to -40 degrees Fahrenheit for winter's worst
  • Item #MHW01CS
[membrane/laminate] GORE-TEX Windstopper (2-layer), [face fabric] 30D nylon ripstop, [lining] 20d nylon taffeta
850-fill down
Max User Height
[regular] 6ft, [long] 6ft 6in
Shoulder Circumference
Hip Circumference
Foot Circumference
[regular] 49in
Bag Length
[regular] 89in, [long] 95in
Draft Tube
Pad Retainer
Fill Weight
[regular] 2lb 14oz, [long] 3lb
European Norm/ISO Comfort Rating
European Norm/ISO Lower Limit Rating
Storage Sack
Stuff Sack
Stuff Size
8 x 15in
Claimed Weight
[regular] 4lb 10oz, [long] 4lb 10.9oz
backpacking, mountaineering, winter camping
Manufacturer Warranty

Overall Rating

4.5 based on 29 ratings

Review Summary

1 Stars - 0 reviews
2 Stars - 1 reviews
3 Stars - 1 reviews
4 Stars - 3 reviews
5 Stars - 24 reviews

Fits True To Size

Screen reader users: the following list provides a visual scale to illustrate the product fit. Please refer to the heading above for the fit type in text.
Runs smallTrue to sizeRuns large

What do you think about this product?


Selecting an option will reload the available reviews on the page
5 out of 5 stars

May 28, 2024

Best -40 degrees sleeping bag out there

Hands down, the best -40 degrees sleeping bag on the market. I’ve used it for my Himalayan expeditions (Mount Everest, Lhotse, and Makalu). As someone who gets cold easily, the sleeping bag has kept me warm throughout the nights at 26,000 feet in super cold conditions without any issues. I love how it is super lightweight and easy to pack with the compressor bag. It doesn't feel too bulky and fits in my 50L backpack along with other gear and equipment. Can’t imagine using any other sleeping bag on my 8000m expedition.


Originally reviewed on

5 out of 5 stars

May 3, 2024

Perfect for Alaska Winter Camping

I need a Quality -40 bag for a camp and a 100 mile foot race IN Alaska, IN February. This was one of the only ones that has a bag for us 6’4” guys!

Mitch Dulleck

Originally reviewed on

5 out of 5 stars

March 11, 2024

Nice warm bag

I have only had a chance to use this -40 bag one weekend since buying it a month ago for a Minnesota winter camping trip, but I was very happy with the quality and warmth. It packs fairly small considering the temp rating and has good loft. I have been winter camping for years and compared to my old winter bag, the size and weight reduction are key. The only thing that would be a nice addition would be a phone/small gear pocket inside the bag like some other comparable bags.


Originally reviewed on

4 out of 5 stars

January 22, 2024

Nice bag

Initially the bag looks great, good zipper and fabric and loft. Alittle crinkly but not something that would deter me from using it. Looking forward to using it Winter camping.

Amy W

Originally reviewed on

4 out of 5 stars

December 12, 2023

Warmth and Waterproofing! Goodbye uncomfortable Bivis!

Got this for my Himalayan Expedition and used it up to 6300meters. Kept me super warm and having a Gore-Tex fabric meant I was ready for unplanned bivis. Removing one star as the plastic case on the zipper (which keeps the fabric getting caught into the zip) broke. Same thing happened to my friend’s sleeping bag too. Other than that, the product won’t disappoint you.


Originally reviewed on

5 out of 5 stars

April 6, 2023

My sleeping bag of choice!

Definitely my sleeping bag of choice for high altitude or cold weather expeditions! After 30+ Himalayan expeditions and 25+ Antarctic expeditions this sleeping bag is by far my favorite. The combination of high loft for maximum warmth and lightweight yet robust materials make for a superior sleeping bag in the coldest and most extreme environments. The overall design and construction make the bag very comfortable. It wraps around my body so that I have enough space to move around, yet not too much extra room inside. The mummy style goes up and around my head, helping keep my head warm as well on those -40 degree nights! I highly recommend this product to anyone looking to explore or climb in the coldest places on the planet.

Garrett Madison

Originally reviewed on

5 out of 5 stars

April 5, 2023

Amazing sleeping bag

So I have slept 75 nights in this bag at temperatures down to mind 30c and I never had a single cold night. I run survival courses in Sweden and have had many different sleeping bags over the years and this is by far the best. The gortex outer is amazing .. a little noisy but that’s to be expected. I love the size which means you can layer up if need be but I never have had to. Well done keep up the good work.

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Originally reviewed on

5 out of 5 stars

January 20, 2023

Phantom sleeping bag

Love the sleeping bag, stayed warm at -15 hips got cold however.

user image

Originally reviewed on

5 out of 5 stars

December 13, 2022

Winter camping

Camping -30 excellent materials! I was super toasty all night ! Kluane National park Yukon

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Sandra Peña

Originally reviewed on

5 out of 5 stars

August 26, 2022

Tested in the harsh winter of Alaska (Size Reg, Zipper LH)

I am 5’10 and weight 170lbs; I am a side, hot sleeper. Even though I have not tested this sleeping bag to it’s coldest rating, it’s performance was exceptional at -21°F (-29.4°C.) I slept out in the open without a tent or a bivy cover. I slept great but was overheating because of my parka. The wind chill was -27°F, however it didn’t make a difference since I didn’t feel any wind with the outer material (gore-tex windstopper.) It’s not waterproof, but it is water repellent, so it prevents condensation from soaking the down insulation. Some reviews mention it being cold, so keep in mind every sleeping bag rating has been tested with an appropriate sleeping pad and layers. Do your research on how to properly camp at below 0° temperatures. I changed into dry layers and paired it with: Sleeping pad R-Value 6.2 Switchback pad of R-Value 2 Total R-Value of 8.2. Down Parka (800 fill) Down booties Fleece lined base layers Mountaineering socks Fleece gloves Fleece Beanie Fleece balaclava Nalgene with hot water in between legs Also the sleeping bag is fitted for mountaineering, so I slept with my camera, batteries, boots, and gore-tex jacket inside. If you plan on having a lot more gear inside your sleeping bag, you might want to get the size Large. I cinched down the collar all the way and didn’t feel any drafts. There are few bags rated for -40 and below. But I purchased this one because of the gore-tex windstopper and the experience I have with Mountain Hardwear products.


Originally reviewed on