Free 2-Day Shipping on Orders Over $50

Detail Images

  • Arc'teryx - Waist
  • Arc'teryx - Atom LT Insulated Pant - Men's - Black
  • Arc'teryx - Waist -

Current Color

  • Arc'teryx - Atom LT Insulated Pant - Men's - Black

Arc'teryx Atom LT Insulated Pant - Men's


Free 2-Day shipping on orders over $50. Learn More

Select a Size:

Select options
  • Select options
    • S
    • M
    • L
    • XL

    Select a Color:

    Select options
  • Select options
    • Black

    10 Reviews


    Compressible lightweight warmth whenever your legs need it.

    Layer Arc'teryx's lightweight Atom LT Insulated Pant under your hardshell the next time you want toasty warmth in the alpine. Coreloft insulation brings the warmth without the weight in a compressible package so you can stow the pant in its pocket when you don't need it. The Tinthan shell has a DWR coating for water-resistance in case you don't want to wear the Atom LT as a midlayer. An articulated construction makes sure you can climb and ski with a full range of motion. Arc'teryx also added full-length side zippers so you can get in out and of these pants with crampons and boots on.

    • Tinthan shell with DWR coating
    • Coreloft synthetic insulation
    • Trim fit
    • Articulated knees and seat
    • Full-length side zippers
    • One stow pocket
    • Item #ARC004I

    Tech Specs

    Tinthan nylon, DWR treatment
    60g Coreloft
    1 internal stow
    Side Zips
    yes, full-length
    Claimed Weight
    11.6 oz
    Recommended Use
    Manufacturer Warranty

    Tech Specs

    • Reviews
    • Q & A

    What do you think about this product?

    Have questions about this product?

    Full Side Zips But Not Two-Way, Crazy

    • Familiarity: I've put it through the wringer
    • Fit: Runs large
    • Size Bought: Small
    • Height: 5'10"
    • Weight: 155lbs

    Marmot used to make a great product similar to these called Dri-Clime pants..insulated with thin fleece, wind-stopper thin shell on the outside. The perfect all-condition, under-tech-shell-pants for skiing/touring/climbing. With full zips...both ways, of course!
    For an extra 10 cents cost per pair, these could also allow opening the zips from the top with little velcro pulls to keep the wait up (and maybe also adjust the waist, per another reviewer’s good comment. Then you can down zip from the waist both your shell pants and these liners, perfect for ski tours in spring.

    What they said

      Everyone’s reviews of these are right on. Even the bad ones. I agree with everything Malik says in the previous review. I really like them but they could also use a lot of work. They are very warm and very comfortable and very lite. I haven’t used them on the mountain and will update when I do. However, they have strange sizing, could use pockets, need a better waist band, better cuffs, and the tag and interior stow pocket are in very strange spots. They’re also crazy expensive. I now wear my around the house almost every day, dog walks, on the way to the Gym. sizing is weird. I ordered a large and returned it for a medium. I am 190 6foot and 33 or 34 waist. I haven’t worn a medium everbut I do on these.

      sweat resistant and light, a favorite

      • Familiarity: I've put it through the wringer
      • Fit: True to size
      • Size Bought: Large
      • Height: 5'10"
      • Weight: 195lbs

      Think of this piece as a replacement for fleece pants. Similar warmth as fleece, but much lighter, much better at handling sweat, and much more compressible. This is more technical than fleece pants in that it has full side zips so you can put it on without taking off your shoes. It also has a self storage pocket but no side pockets.

      They handle sweat by seeming to move the water off your body and letting air evaporate it quickly. I'm not sure how much water it would take to soak them..but I would guess it's a considerable amount since they have handled any sweat I've thrown at them so far.

      Did a lot of research but was skeptical of this piece at purchase time. It's won me over so hard.

      I run at night a lot, but frequently got cold after running when I grabbed dinner or travelled home. I carry this now in a small backpack with my headlamp and other essentials. It's light enough I don't notice it, and compressible enough it doesn't bother me during the run. I put these on and they are fine even if I'm sweaty. They breathe well so I dry quickly and stay dry.

      Previously I tried long sleeve shirts or jackets (heavier/bulkier), light sweats (less warm, heavier, and terrible when wet) or light running pants (less warm or less breathable and they didn't handle sweat like this does).
      This has worked well with temps in the 50's/60's. The side zips are effective to manage some higher temps, but the piece is pretty warm and gets too hot quick once you get to the low 70's.

      I'm looking forward to layering it on the slopes on super cold days.

      A few minor improvements requested:
      - its not really clear which way is front/back, because the pocket and label are at the front/ unusual choice.
      - the pocket in the front feels like it should be in the back... it's weirdly placed.


      • Familiarity: I returned this product before using it
      • Fit: Runs large
      • Size Bought: Medium
      • Height: 6'2"
      • Weight: 185lbs

      For the price ($250), just not that great. There is no way to adjust the waist -- just has an elastic waistband. For this price you should have velcro, a string, even a belt loop. The medium is too big if your waist is 33" or less -- they don't stay up. Hard to believe they didn't add any kind of ability to adjust the waist.

      No hand pockets. No crotch zipper.
      The ankle pull ties just bunch up the fabric around your ankle.

      Better to go with the Mountain Hardwear Compressor Pant or the Patagonia fly fishing pants over these.

      Winter Essential

      • Familiarity: I've put it through the wringer
      • Fit: True to size
      • Size Bought: large
      • Height: 6'0"
      • Weight: 160lbs

      Throw these over your jeans anytime the temp is 25 or less and your butt will thank you. Not meant to deal with abrasion, these are not shell pants people. However as far as warmth I have used these from 25 to -10 and they kept my legs warm just fine even out walking to the store. They also are easy to remove and put on with the side zippers and they stash in their own pocket. Awesome work Arc'teryx!

      Great Midlayer Pant

      • Familiarity: I've used it once or twice and have initial impressions
      • Fit: True to size
      • Height: 5'9"
      • Weight: 150lbs

      Very comfortable, however the fabric seems to be very fragile.

      I live in these all winter

      • Familiarity: I've put it through the wringer
      • Fit: True to size
      • Size Bought: small
      • Height: 5'3"
      • Weight: 130lbs

      I bought these pants to wear under my shells on cold storm skiing days but I find myself wearing them around the house (and public) like sweat pants. Great for camping, casual use and just anytime you don't want your legs to be left out of the warmth. Why did I never think of getting a jacket for me legs sooner?


      • Familiarity: I've used it several times
      • Fit: Runs large
      • Height: 5'7"
      • Weight: 165lbs

      I use them like sweat pants in the winter. You can throw them on and wear them to the grocery store if your lazy like me that works well. I also like them for those rare days when a base layer is not enough on the legs up on the hill.

      Fantastic mid layer

      • Familiarity: I've used it several times
      • Fit: True to size
      • Size Bought: Medium
      • Height: 6'1"
      • Weight: 170lbs

      Borrowed my neighbors set to do some skiing and I just had to buy a pair myself. Bought these for cold days on the mountain when that extra layer is needed. Have taken them out on the slopes as well as some hiking activity.. warm and cozy is definitely true.. almost too warm and cozy but they have been a great layer to add than what I previously had. The inner pocket is useful, the full length zippers work well. No complaints so far when treated as a mid layer.


      • Familiarity: I've used it several times
      • Fit: True to size

      After buying these to take on a recent NZ mountaineering trip. I wore them on a multi pitch mixed alpine route one day and they got all ripped and torn up pretty bad. The outer material is very prone to be torn easy. these might be better suited to only wearing them as BC or in the hut not recommend to be climbed in. I now own a pair of MH Compressor pants that have reinforced bum and knees.