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  • With a European Norm (EN) lower-limit rating of 35.4°F, the Atom Sleeping Bag is suitable for 3-season use
  • Certified 800+-fill goose down is treated with Down Defender to improve water resistance in wet conditions
  • Sewn-through, smooth-curved, stretch tricot baffles keep down from shifting
  • Nautilus multi-baffle hood with drawcord limits heat loss
  • Anatomic footbox with wraparound construction increases warmth
  • Fold-down second zipper adds ventilation and easy access
  • Pertex® Microlight ripstop nylon shell is ultralight yet strong and durable
  • Locking YKK 2-way zippers with zip-guard sliders are backed with snagless, insulated draft tubes
  • Zipper garage keeps zipper pull in its place during the night
  • Internal stash pocket
  • 2 hang loops for storing or airing out bag
  • Stuff and storage sack included


Many sleeping bags are rated for temperature by an independent testing protocol, the European Norm (EN) 13537. Each bag gets two ratings: a Comfort rating and Lower Limit rating. The Comfort rating is the lowest temperature at which the bag will keep the average woman (or "cold sleeper") comfortable, and the Lower Limit rating is the lowest temperature at which the bag will keep an average man (or "warm sleeper") comfortable. Everyone's body and sleep comfort is different, so EN Ratings are merely a guideline to help you compare products.

View all Marmot Men's Sleeping Bags

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Best Use Backpacking
EN Lower Limit 35.4 degrees Fahrenheit
EN Comfort 44.1 degrees Fahrenheit
Temperature Rating (F) 40 degrees Fahrenheit
Temperature Rating (C) 4 degrees Celsius
Long Left
1 lb. 8.5 oz.
Regular Left
1 lb. 4.7 oz.
Shell Nylon
Zipper Location Left
Insulation Type Down
Water-Resistant Down Yes
Fill 800-fill goose down
Fill Weight
Long Left
10.5 ounces
Regular Left
8.6 ounces
Lining Nylon
Sleeping Bag Shape Mummy
Fits Up To (in.)
Long Left
78 inches
Regular Left
72 inches
Shoulder Girth (in.)
Long Left
63 inches
Regular Left
61 inches
Hip Girth (in.)
Long Left
58 inches
Regular Left
56 inches
Stuff Sack Size 6 x 12 inches
Stuff Sack Volume 5.6 liters
Compressed Volume Unavailable
Gender Unisex
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Is the zipper a full length zipper?

Asked by: Numbers
​The zipper on the Atom Sleeping Bag is a full length zipper.
Answered by: REIservice
Date published: 2017-01-21

Is this basically the warmer weather version of the Hydrogen bag by Marmot? Also, is this bag compatible with additional layers to potentially increase warmth for colder trips?

Asked by: Stephen
Yes, both sleeping bags are high quality, 800-fill down bags. You can increase the warmth of the Atom by including a sleeping bag liner, bringing the warmth to a level comparable to the Hydrogen.
Answered by: REIservice
Date published: 2017-03-31
  • y_2017, m_6, d_23, h_1CST
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