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  • Marmot - Atom Sleeping Bag: 40 Degree Down - Team Red/Redstone
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  • Marmot - Atom Sleeping Bag: 40 Degree Down - Team Red/Redstone

Marmot Atom Sleeping Bag: 40 Degree Down

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    • Team Red/Redstone

    5 Reviews


    Save some real weight.

    You could delude yourself into thinking that snapping your toothbrush in half and cutting the edges off your maps is actually going to save you some pack weight, or you could get the Marmot Atom 40 Degree Down Sleeping bag and actually save about two pounds. Being the lightest offering in Marmot's ultralight line, the Atom weighs a feathery one pound six ounces in the regular length, and maintains the lofty comfort you'd expect from a 800-fill down sleeping bag, so you'll stay warm as long as temperature hover above freezing.

    The Atom may be light, but it certainly isn't lacking in features. Sure, its Pertex Microlight fabric is light, but it's also breathable and water-resistant thanks to its DWR finish. The down fill has also been treated to repel moisture, so the fibers won't instantly clump and lose insulating properties if the bag should get wet. The Atom is available with either a left- or right-handed full-length zipper with an additional zip on the side, which creates a fold-down feature for those times you're sitting up in your bag, tent-bound and waiting for a storm to pass. To keep the Atom comfortable when it matters most, Marmot used a curved baffle construction to prevent down from wandering during your sleep adventures, and added an anatomic footbox to give your dogs some extra room to run around when you're dreaming about hiking.

    • 40-degree temperature rating
    • 800-fill down insulation
    • Down Defender water-resistant treatment
    • Pertex Microlight fabric with DWR
    • Mummy shape with anatomic footbox
    • Fold-down second zipper
    • Curved baffle construction
    • Stuff sack included
    • Item #MAR00T3

    Tech Specs

    Pertex Microlight (20D nylon ripstop), DWR finish
    800-fill down
    Max User Height
    [regular] 6 ft, [long] 6 ft 6 in
    Shoulder Circumference
    [regular] 61 in, [long] 63 in
    Hip Circumference
    [regular] 56 in, [long] 58 in
    Foot Circumference
    [regular] 39 in, [long] 41 in
    Bag Length
    [regular] 81 in, [long] 87 in
    Draft Tube
    Fill Weight
    [regular] 8.6 oz, [long] 10.5 oz
    40 F
    Stuff Sack
    Stuff Size
    6 x 12 in
    Claimed Weight
    1 lb 6 oz, 1 lb 8.5 oz
    Recommended Use
    backpacking, ultralight backpacking
    Manufacturer Warranty

    Tech Specs

    • Reviews
    • Q & A

    What do you think about this product?

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    Amazing and light

    • Familiarity: I've used it several times

    I am a very warm sleeper and have been looking for a decent bag over 30 degrees. This definitely is the winner I have been searching for. Very light weight and compressible! Warm enough for chilly nights (~35ish) but I am not waking up in a sweat desperate to open the side. I've been able to sleep through nights in the upper 20's with some heavyweight baselayers and a sweater without a problem, but I do tend to run pretty warm naturally. This combined with a small thermarest camping pillow has been amazing for summer backpacking trips. Definitely recommend picking this up if you're looking for a light, not too warm sleeping bag that saves on space in your pack.


    • Familiarity: I've used it once or twice and have initial impressions

    I got the Long Atom. This bag is light and compresses great. I'm a big guy, 6'2 / 205lb. XLarge everything. I need a 50L pack to pack the same stuff my wife puts in a 30L. I got this bag to reduce the space needed for back&bike packing. The lighter weight is an added bonus. I'll still use my synthetic bag for canoe trips b/c everything always gets wet. I got the Long Atom, saying big atom makes me chuckle. Pls send me some black goats for my CX and MTN bikes.


    • Familiarity: I've used it once or twice and have initial impressions

    Because it's winter I've only used this a few times, but so far it's been great. It is very warm -especially for its weight. The size/weight will make this bag great for backpacking. So far this bag has met my every expectation.

    packs small, lightweight

    • Familiarity: I've used it several times

    This is my go-to bag for all my bikecamping trips. In a hammock I have been comfortable down to the low 50's with a tshirt, shorts, and a pad between the layers and no underquilt. In a tent with fleece pants, socks, light weight down jacket, and wool hat I was on the warm side down to mid 30's. If it's going to be cold I am going to have my jacket, socks, and pants anyways regardless of the bag I bring. I save the weight and pack size of a larger and warmer bag and just wear all my layers. The zipper is good, relatively few snags. The foot box is not claustrophobic and I like the simple single draw for the hood.
    *I am a warm sleeper
    **I have last years model (2015?) with the horizontal baffles and 850 fill.

    Nice bag!

      I recently took this sleeping bag on a 6-day self-support kayak trip in Eastern Oregon. Size and weight were both critical and this product was perfect! When the temperature got down below freezing the bag was comfortable along with my lightweight down sweater. As we descended the canyon the air temperature warmed up and the bag alone was fine (night temperature around 38-40 degrees). This will be my go-to bag for ultralight trips in the future.