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Description

The combined power of Pertex Microlite and 850+ fill down is a beautiful thing.

The Marmot Atom 40-Degree Down Sleeping Bag relies on high-loft, premium-quality 850-fill goose down for its incredible warmth-to-weight ratio. An ultralight ripstop shell holds the insulation in place without adding much weight or bulk for easier compressibility. Take the Atom along on your next summer backpacking trip—it's so compact and lightweight, you'll have no trouble finding space for it in your pack.
  • EN comfort-rated at 50-degrees F for mild summer conditions; lower-limit-rated at 43-degrees F for occasional use during late spring or early fall
  • Premium 850-fill goose down packs down well, rebounds nicely after repeated compression, and features a high warmth-to-weight ratio
  • Ultralight Pertex Microlight ripstop shell is highly breathable, water-resistant, and resists abrasion and wind like a champ
  • DWR finish on the fabric repels frost, dew, and condensation
  • Down-filled full-length draft tube protects against areas where cold can creep in unexpectedly
  • Nautilus 6-baffle hood wraps around your head and provides 3D protection against heat loss
  • Hood Muff is a warm down gasket around the face designed to keep heat in while keeping the drawcord away from your face
  • Sewn baffles save weight ensure that the insulation stays in place so you don't suffer cold spots
  • Stretch tricot baffles at foot and head regions extend the life and shape of bag and improve warmth retention
  • Large trapezoidal foot box decreases constriction at the bottom of the bag
  • Ground-level seams help prevent heat from escaping upwards through seams
  • Nylon stuff sack and a storage bag included
  • Filled and finished in Santa Rosa, California

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Marmot Atom Sleeping Bag: 40 Degree Down

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Here's what others have to say...

4 5

Yung Lee

Member since 
  • Familiarity: I've used it several times

This is a reasonably priced (because you can regularly find it on sale for 10~20% off) and a very versatile sleeping bag that you can use as a 3 season bag if you sleep cold.

The good:
I've used it down to low 30s in just base layers at Shenandoah in November last year with Thermarest Trekker with a relatively low R-value of 2.0; I won't say I stayed warm, I felt cold during the night, but it wasn't horrible either. I'm 5'11", 170~180lbs (depends on the season), circumference around my shoulders (so the widest part of my body) is about 47", and the regular fits me very well in that it keeps in the heat well yet it leaves me enough room inside so that I don't feel cramped. The Pertex inner lining is silky smooth to touch.

The bad (minor):
My regular WITH the stuff sack weighs 22.7 oz (the stuff sack is 0.6 oz), so mine weighs about an ounce more than it's listed. The zipper can get caught at times despite the zipper guards, so that's the only minor complaint that I have.

Overall, a very solid 2/3 season bag (depending on how cold you sleep), and can compress very small if you like to pack light for your trips.

5 5

anton2159384

Member since 

Love it. Very light, packs very small and a great bag for my Utah spring-summer-fall trips. Used it for about a year now. Seriously, very happy with it.

2 5

dimi

Member since 

Hi, Im not normally a cold sleep, i got this to replace my 30 deg (mammut synth bag) bag because it was way too warm. i've only had it down to about 8 or 9C and was really cold, even with icebreaker 200 wool and a hat. do you think i got a under-filled bag? Im not a cold sleeper normally, quite the opposite in fact. im not sure what to do.

5 5

Ryan Silve

Member since 

Compresses well, immensely comfortable, unbelievably lightweight (a large Arnold Palmer weighs the same), and far warmer than its temperature rating suggests. The 850 fill down gives it an advantage over its brother, the Marmot Arete.

It's closest competitor is the Mountain Hardwear Phantom 45 but the Atom has a higher fill power, and additional fill weight contained inside. The Pertex coating is nice, allowing the bag to easily shed the cold dew of an early morning or negate any condensation problems your tent might have.

Get it, you won't regret it.

5 5

Matthew Forrest

Member since 

Very nice very very light. I just got it so I can not comment on warmth yet but ill check back once the weather warms up a bit. This Atom has a pertex shell not the lightforce nylon of years past. although it has the same dimensions as the pinnacle and arete bag it is not as roomy. shoulder girth is the same but seems smaller in the elbow area for some reason. Still comfortable though. I am 6 foot 3 225. Packs super small and plan to use it as a bag liner in my pinnacle bag for the rare below zero camping trip, and obviously as my summer bag.

What the heck is a draft tube???

Garrett Perkins

Member since 
Posted on

What the heck is a draft tube???

DEON NORTJE

Member since 
Responded on

It is that extra strip of material on the inside of the zipper that ensures that you do not have draft coming through the zipper area.

ray_trot1827587

Member since 
Responded on

It insulates the zipper to help retain body heat.

Phil Maher

Member since 
Best Answer Responded on

In this picture (not a Marmot though), you'll see the draft tube. It's the long, black insulated tube that runs down the length of the zipper. In the foreground, you'll also see the green draft collar that insulates around your neck between the hood and the body of the bag. Both are important features to look for in quality mummy bag construction.

In this picture (not a Marmot though), you'll see the draft tube. It's the long, black insulated tube that runs down the length of the zipper. In the foreground, you'll also see the green draft collar that insulates around your neck between the hood and the body of the bag. Both are important features to look for in quality mummy bag construction.

Not really a question, but important...

Brian Donner

Member since 
Posted on

Not really a question, but important nonetheless. The Marmot Atom is a sweet bag and I'm not saying don't buy one, but isn't the lightest 3 season out there. The Western Mountaineering Summerlite is a 32 degree down bag that weighs in at 1lb 3oz. So, sorry to be a bubble-burster. I love my Marmot Lithium, but I also love my summerlite.

The description says it weighs 16oz, this is incorrect. The reg. is 21.52oz according to Marmot.

Two cents... Happy Trails!

Kristoffer N Jensen

Member since 
Responded on

MTHW's Phantom 45 is also a bit lighter, 1-2 oz :)

5 5

lkd4109313

Member since 

I did a lot of research to find the right sleeping bag for 30-50 degree nights. I narrowed it down to the Marmot Atom and Big Agnes Horse Thief. I had trouble deciding which to get so I got them both so my wife would have one. My wife and I were both cold all night in the Horse Thief, which I returned because it was badly over rated and over priced for the way it performed. I really liked the design and wanted it to work but you cant sleep shivering. The Atom performed better than expected. I slept comfortable in a 1-person tent on nights of 30 and 33 degrees with long underwear. Very comfortable and packs easily to near nothing without a compression sack. It warms up instantly and is so light you can not feel the bag on you. Good product!

3 5

Mark Gardener

Member since 

Recently I bought a Marmot Atom and I was highly impressed by its weight and excellent design. However, when I tested this out camping in Northern Chile for a week with temperatures of between 5 and 10 C (40 and 50 F) I had an unpleasant discovery: this bag is nowhere near capabale of its supposed minimum. Even with my entire stock of warm clothing on I just managed it keep warm. Basically it seems the reason Marmot was able to make this bag so light is that they didnt put any down in it. My advice: this is a good bag but buy one that has a much lower rating than your needs

Sam Furner

Member since 
Groups:
Responded on

It is so much warmer in a sleeping bag with only undergarments on than wearing all your clothes! Cold air is trapped in the bag with you when fully clothed and you're better off shedding a few layers before getting in.
Really one should be in the buff. If you wear any clothing, you will sweat into them, rendering them useless and in fact you will get very cold very fast. Your body heat will insulate the bag, but it can't do that if you're dressed. Trust me!

Does this bag come with a stuff sack?

cdk4093019

Member since 
Posted on

Does this bag come with a stuff sack?

Tim Coats

Member since 
Groups:
Responded on

Yes it does.

moroni

Member since 
Responded on

A generous size storage bag is also included.

5 5

Erich Knaak

Member since 

Took this bag on a 4 day trip in the Enchantments and have no complaints. It's light and packs very small. At temps in the low 50s in a Rab eVent Superlight bivy it was plenty warm. I'm looking forward to some cooler nights to see how low I can go with this thing. I'm 6'1" with broad shoulders and have enough room to move around in the long version. I'm very happy with the warmth to weight ratio.

4 5

KrazyGirl152

Member since 

So far this bag is great. Comfy, soft, and lightweight, and packs up great. This bag doesn't come with a stuff sack though, you have to purchase that separately.

4 5

dca3824771

Member since 

This bag is wicked light - which is why I wanted it in the first place... however, It's not quite as warm as I hoped. I use it with a THICK thermarest camp rest and inside an OR GoreTex Bivy. I sleep very warm typically, but have been chilled on a few late september trips where I doubt the temp dropped much if any below 40 degrees. Had to put my down vest in with my feet. There was a bit of wind exposure in both cases. With my wide pad in the bivy i get cold spots where there's any pressure on the bag. Still a good bag and works well up to September as long as you don't get a cold front. I'm used to temp ratings in my Western Mountaineering bags easily exceeding the rating so was slightly disappointed. If weight's your main deal and you don't intend to push the rating this is still a fantastic choice. If you're thinking full 3 season bag (October) in the rockies, better rethink and get a 20 or 30 degree bag minimum.

The Backcountry description says 1Lb or...

cmf777az528828

Member since 
Posted on

The Backcountry description says 1Lb or 16oz, but under the Tech Specs and other places I've checked it says 1lb 5oz or 21oz. Which one is it? Is the actual bag itself minus stuff sacks 16oz? Otherwise it's hard to see why you'd pick this over the 24oz Marmot Arete? Thanks in advance

Dakka

Member since 
Best Answer Responded on

1 lbs 5 oz / 610 g

5 5

js1924119

Member since 

The other reviewers have pretty much hit it on the head. This bag is amazing. First, it fits into an XXS stuff sack fairly easily, takes no more than 3 minutes to stuff it. When you take it out of the stuff sack, i would estimate it takes about an hour to get its full "fluff" back. At first, I was weary because it doesn't appear to have a much fill as my old Conness, but after using it on some cold nights, my worries were abated. This will keep you warm below 40deg, I used it at around freezing (guessing because there was frost on the ground) and it was plenty warm. Combine this with a NeoAir and you have a sleeping set-up that's around 2lbs 3oz. Not bad for the ultra-light nuts such as myself. Another added plus, Marmot gives you a nice big storage sack for your bag when your not using it.

5 5

dfrye132288608

Member since 

This bag is great. I had a regular (read short), fat, and heavy 30 degree synthetic that weighs 3+ lbs before I bought this. Now my long version Marmot bag weighs in at 1lb 10oz and packs down super small. It's true to the 40 degree rating and great for spring summer and fall. I've even thrown in a lightweight fleece liner and slept comfortably below freezing at Blue Lakes near Ridgway, CO. Would definitely recommend! (I found this for cheaper at another site but wanted to buy from backcountry because they're awesome...and they matched the price)

What´s the best choice for a three season...

YinYang

Member since 
Posted on

What´s the best choice for a three season sleepingbag, Marmot Atom or Western mountaineiring Ultralight?

YinYang

Member since 
Responded on

And between Marmot Hydrogen or Western Mount. Alpinlite? What are the differences between their outer materials? What is the maximum stuff size for both models?

5 5

Brandon Smith

Member since 

All of the 850+ fill Marmot bags are incredible. The atom is my spring, summer, and fall bag. Get a helium for a winter bag. I've used it below freezing and broke a sweat in this bag. This bag is insanely light and packs so small. Don't waste your money on other bags. It's expensive but worth every penny. I'm 6'0 and use the long.

How waterproof/resistant is this bag? I'm...

Acire747

Member since 
Posted on

How waterproof/resistant is this bag? I'm looking for something to sleep in the open air with - on 60-70 deg nights that consistently rain for 10-20 minutes per night. I'd appreciate your recommendations!

moroni

Member since 
Best Answer Responded on

At the very least you'll need a bivy sack. This sleeping bag by itself would be totally useless in any kind of rain. Considering your usage, I'd choose a bag with a Dryloft/Gore-Tex/GWS shell in combination or even a synthetic. Check these out to compliment this sleeping bag:

http://www.backcountry.com/store/group/216/Bivy-Sacks.html

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