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Western Mountaineering UltraLite Sleeping Bag: 20F Down

$510.00 - $540.00

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  • 5ft 6in/Left Zip
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  • 6ft/Left Zip
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  • 6ft/Right Zip
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  • 6ft 6in/Left Zip
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  • 6ft 6in/Right Zip
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Ultralight and ultra lofty.

The Western Mountaineering UltraLite Sleeping Bag lives up to its name by keeping your load manageable while still packing in a hefty dose of premium 850-fill down for those chilly nights. A soft taffeta lining caresses trail-weary skin and, thanks to the ExtremeLite shell's breathability, the climate inside of the bag stays comfortable on balmier nights.

  • Breathable, ultra-light, packable, and high-thread-count ExtremeLite shell fabric encases the insulation without adding unnecessary weight
  • Packs 16 ounces of ultra-premium, 850-fill down insulation to retain your body’s warmth and maintain a super-high warmth-to-weight ratio
  • Interlocking draft tubes and a down-filled collar prevent energy-sucking drafts from zapping your slumber
  • Slightly narrower shoulder girth helps eliminate pockets of dead air for improved warmth retention
  • Western Mountaineering bags are made in the USA
  • Item #WES0031

Material
[shell] ExtremeLite, [lining] nylon taffeta
Insulation
850+ fill down
Shape
mummy
Max User Height
(short) 5 ft 6 in, (regular) 6 ft, (long) 6 ft 6 in
Shoulder Circumference
(short) 59 in, (regular) 59 in, (long) 60 in
Hip Circumference
(short) 51 in, (regular) 51 in, (long) 52 in
Foot Circumference
(short) 38 in, (regular) 38 in, (long) 38 in
Fill Weight
16 oz
Degree
20 F
Storage Sack
yes
Stuff Sack
yes
Stuff Size
7 x 13 in
Claimed Weight
(short) 1 lb 12 oz, (regular) 1 lb 13 oz, (long) 1 lb 15 oz
Recommended Use
ultralight backpacking, camping
Manufacturer Warranty
lifetime

Tech Specs

What do you think about this product?

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>Rating: 5

No comparison

Familiarity:
I've put it through the wringer
Fit:
True to size
Height
5` 7"
Weight
145 lbs

This bag is the perfect mix of warm and lightweight for 3-4 season sleeping. There is simply nothing bad about this bag. WM is the best.

>Rating: 5

Love this bag

Familiarity:
I've used it several times

I have had this bag for over 3 years and absolutely love it. It keeps me so warm you don’t need long underwear. I have slept in it at least 50 times.

>Rating: 5

Bike Packing Essential

Familiarity:
I've put it through the wringer

For 2 years, this has been my December bike trip sleeping bag. Holds up great getting packed in a stuff sack every day for 2 weeks. Slept perfect down to 20 degrees on several nights with a light baselayer. Use it as a quilt if temps get up to 50. Best bag I have ever owned.

>Rating: 5

Sweet comfy dreams!

Familiarity:
I've used it several times

Wow, this bag is amazing and I am in love. I brought this bag on my most recent trip backpacking in the Sierra Nevada’s on the John Muir Trail, and this was one of my absolute favorite pieces of gear! First off, the weight of this bag is crazy light. When I first got the bag in its stuff sack, I could hardly believe that there was anything inside (not even exaggerating that much…well, maybe a little). At 1lbs 13 oz, this bag is about as lightweight as you can get for the warmth without switching to quilt systems. The lightness of the bag matches the packability of the bag. With a Sea to Summit Event Dry Compression Sack (14L), this thing stuffed down to the size of a BearVault450 (about the size of a gallon of milk). When sleeping at night, with temperatures around 40-50 degrees, I was nice and toasty warm. The down surrounded me like a puffy cloud. Even though it didn’t get down to super cool temps, I have no doubt that this bag will keep me warm through fall/warmer winter nights. I am excited to love the heck out of this bag! Before getting this bag, I had heard that Western Mountaineering made amazing sleeping bags and I am absolutely sold. Weight and space was the name of the game and this bag met every expectation and exceeded it. This bag is worth every cent. It is 20 degrees of sleeping bag wonder.

Wow,
>Rating: 5

Nice

Everyone at camp freezes while I stay warm.

>Rating: 5

Incredible sleeping bag

This is not my first 20 degree sleeping bag, but it is definitely the warmest. I have never slept in a bag that that was so true to its rating. I took this bag out on a camping trip down in the desert this weekend. It got down in the 30s at night while we were camping and I was so toasty. I only slept in a very thin baselayer like I always do, and had to unzip my bag I was so warm. THAT NEVER HAPPENS! As soon as I crawled in I instantly felt the warmth and it has to cinches to keep heat in. One around the collar, and one around the hood. I love the collar cinch because I kept my pillow inside the hood of the bag, and this can creat a draft around my shoulders. But because the collar cinched around my neck, I was able to keep all the heat inside. The other thing that shocked me was how a 20 degree bag could compress so small and be so lightweight. I cannot wait to use this on my next backpacking trip this summer because it's going to decrease my base weight by about a pound which is huge. It will allow more space in my pack which is great for when I want to bring an extra luxury item, or just tighten it down a little more and have a more compact pack. This sleeping bag is incredible and worth the money in my opinion. You won't find a sleeping bag as warm and as lightweight as this one. I can't wait to take it on many more adventures.

Many thanks for the review, Hailey! Leta Western Mountaineering Rep

>Rating: 5

I'm in love!!

Familiarity:
I've used it several times

Hands down the best sleeping bag I've every used. First off they have a lining that keeps the zipper from catching!! Such a great feature. Also the bag packs down so well and small. It is unbelievable. I know the price point is a bit high on this bag but it is so worth for the quality you are getting. This bag is perfection form the small details to the signature of the person who did the stitching. I highly recommend and once you use a Western Mountaineering Bag you will never go back to anther company. They are the best hands down.

Thank you Sam! Happy Trails! Leta Western Mountaineering Rep

>Rating: 5

I love this bag!

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

I asked my sister (NOLS instructor) for a recommendation for a sleeping bag, and of course she recommended the best. I don't camp a lot, but I wanted to only buy one sleeping bag vs trading in a cheaper one in a year or two. I used this in the desert and was plenty warm - it probably got down to 30 degrees at night. I also love how small it packs up. Its super light weight too, not big and bulky,

>Rating: 5

Best Backcountry Sleep I've Ever Had

Familiarity:
I've put it through the wringer

I've used hand-me-downs and secondhand bags for as long as I've been camping and backpacking. My last bag - a synthetic, 35º TNF bag purchased secondhand nearly five years ago - no longer had much warmth value and was incredibly bulky and heavy for it's rating. When I finally treated myself to my first "nice" down bag - this Western Mountaineering UltraLite - it was like crossing through the pearly gates of backpacking sleep after toiling away in restlessness purgatory for short of eternity...or whatever. A few specific things I love about this bag: the down is responsibly sourced, the draft collar truly traps heat, it's lightweight and packs small, and the bag is incredibly easy to zip (super important!). The 20º rating is pretty spot on - I had this bag out on a trip where I cowboy camped in nighttime temperatures between 15º and 45º. I was warm down to 20º and started to feel a chill below that. I also started to slow roast around 45º but your mileage may vary. A final note about size: I'm pretty slim so the narrow shoulders of this bag suit me well but if you've got a broader chest/shoulders, consider the AlpineLite. Otherwise, buy this bag and experience true backcountry bliss.

Thanks for mentioning the AlpineLIte as an alternative for people who want a little more room. Comparison here: https://www.outdoorgearlab.com/reviews/camping-and-hiking/backpacking-sleeping-bag/western-mountaineering-alpinlite-20

>Rating: 5

Best ultralight sleeping bag hands down

Familiarity:
I've used it several times

Took this bag to Patagonia to test out how good it really is. Packs down super small to fit all your climbing gear and more, plus it's durability and warmth is unmatched.

Excellent! Thank you for the review, Talina! Leta Western Mountaineering Rep

>Rating: 5

Very Impressed

Very impressed with this bag. I was at Active Endeavors the other day looking for a new cold temp bag and they had a bunch hung up in the store. take 20% off coupons from coupon-code.info

>Rating: 5

Perfect all around bag

Western bags are the only line I will recommend to friends. They are sewn in the US and only use the finest materials. The bags hold up great, are true to the warmth ratings and are usable all year round.

Thank you! Leta Western Mountaineering Rep

>Rating: 5

USA made!

Familiarity:
I've used it several times

I love these Bags. They have never given me problems with warmth, they compress down nice and compact and are very light. I have been below 20 degree's with 0 issues. Has held up great!

>Rating: 5

Perfect!!!!

I know there are a large amount of people out in the ultralight community that have different opinions on sleeping bags. For the type of hiking I do(alpine, variable climates,frigid nights and long treks) this is exactly what I needed. This bag is light, and is VERY true to its rating. If you want to rest assure this is your bag. Its pricy because it’s quality built. I do upholstery work on Hot Rods and I know quality hand stitching when I see it. These guys take pride in the work they do. Made in the USA!

>Rating: 5

Seems Awesome!

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

I've only used this bag once so I don't know how it will hold up but my first impression was great! The bag is warm and comfortable and packs down very small.

Thank you Matthew! Leta Western Mountaineering Rep

>Rating: 5

impressive quality and warmth

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

Bought this as a gift for a friend and here's what he had to say: I didn't want to sacrifice warmth or weight, and this seemed to be the bag to get. Cursory impressions- fluffy, lightweight, toasty warm, packs down small, and great build quality all-around. Can't wait to test it on a trip!

Amelia! Sorry I missed responding earlier. Thank you for passing this along. Leta Western Mountaineering Rep

>Rating: 5

Packs as small as a nalgene!

Familiarity:
I gave it as a gift but have feedback to share

From my friend: This bag is light weight and with a compression sack, packs down to the size of a large Nalgene. It is a good bag for summer but 20 degrees is a stretch. Maybe 40 degrees for comfort even with a pad. Excellent quality. I am 6’3” and the long fits well. Recommend this bag for warmer summer temperature.

>Rating: 5

Great Sac

Familiarity:
I've used it several times

Love this thing. The inner lining against the zipper is made so you can't zip up the bag in the zipper.

>Rating: 5

HOLY!

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

I've eyed WM bags for three years, but getting by during the California drought with an old bag someone left in my car ;0. Alas the long winter finally came and where we were sleeping on dirt the past few summers, we're laying on the deep snowpack of the 2016-17 Winter. I snagged this bag on a Wednesday night with the help of a gearhead, got extra help to make sure I had it in time for my trip, THEN got a call the next day from my dedicated gearhead who set me up with a change in size to make sure I was getting the full 20degrees. Boy did I! Camping under the Palisade Glacier in my 4season tent, I was snug as a bug in this one. True to temp rating and fully able to go base layers only in a cold Sierra night (first time winter camping). Love the drawstring system, incredible build, packs light. Now just need a better stuff sack to fit in my smaller touring bag so I can keep skiing through the summer!!! 5'6" in a 5'6" bag. perfect.

I've

Thanks for the review Will! Super helpful to get this feedback out to the community.

>Rating: 5

Toasty!

Familiarity:
I've used it several times

This bag is amazing - super light and packs up quite small. I took it on a camping trip where the lows were in the teens and was cozy all night. As someone who moves around a lot in their sleep, I appreciated the roominess in the shoulder and hip area so I could flip onto my stomach and not be twisted up like has happened with other bags in the past. I'll be a Western Mountaineering customer for life!

Thanks Andy!! Leta Western Mountaineering Rep

>Rating:

This will be a little long. Apologies. I'm looking to upgrade on my Mountain Hardware UltraLamina 15, which is now 7 years old or so. I sleep quite cold, and am often uncomfortably chilly in the Lamina, even with layers at temps well above the rating (say 35-40 degrees). Interested in taking the Western Mountaineering plunge, but want to make sure I get an upgrade in warmth with whichever bag I chose. Weight, packability and flexibility are important, but I'm happy to add a few ounces to be toasty. I'll be using the new bag for a backpacking trip in Europe and Nepal this fall. Temps at the camp in Nepal where I'll be are not frigid (reportedly 25-30 degree lows during the coldest months). I mostly do 3-season stuff, so at or a little below freezing is the lower end of what I'll encounter. But again, I sleep real cold. Thoughts from WM experts/fans? How would the WM UltraLite compare to my UltraLamina 15 re warmth? Should I go warmer with the VersaLite? Overfill the UltraLite? Even warmer? Thanks ahead of time for any help!

Jon - great question - sounds like you sleep a bit cold. I would definitely recommend the Versalite. Even if the temps are warmer, you can move the down from the top of the bag to the bottom, so you have less on you. I also like the dimensions of the Versalite bag over the Ultralite. The Ultralite is narrow and efficient, but I get claustrophobic. You will love it!! Leta Western Mountaineering Rep.

>Rating:

Hello, I try to compare this sleeping bag with some europeen supplier but i struggle : In Europe we use the norm EN 13537, wich specify : -Comfort temperature : women 60kg lying position -Limit Temperature (or limit comfort temeprature) : men 70kg Fetus Position -Extrem Temeprature : Risk of death In Us there is only the comfort temperature given : Is it comparable to our comfort temeprature ? What would be the Limit Temperature for the Ultralight Western Mounteinering sleeping bag ? Thx in Advance Eric

Hey Eric! Thanks for asking. I got the answer from our Western Mountaineering rep for you and also emailed you a copy of the entire catalog + EN ratings. To answer you questions here: 1 Comfort rating: 25F or -4C 2 Limit Rating: 14F or -10C 3 Extreme Rating: -21F or -29C Please note that the EN 13537 standard temp testing produces inaccurate data for extreme cold weather bags.

Thank you for the response, Koly! Hope this works out for you Eric. Great bag! Leta Western Mountaineering Rep

>Rating:

Is the fill weight, 16 oz, the actual weight of the bag? Or how heavy is it? And what's the volume of the packed/compressed bag? My current bag is 5 L and 856 g. Thank you!

Hi Kyle the UltraLite has a fill wt of 15oz, 16oz and 17oz for the three sizes. The total wt are 1lb 12oz, 1lb 13oz, and 1lb 15oz for the three sizes. The stuff sack size is 8L. Let me know if I can help answer any other quetions for you on this sleeping bag or any others.

>Rating:

Options! Love them, but I'm trying to figureout what will work best for me. I am typically a cold sleeper (female), I'm 5'7" 140lb, side sleeper but I roll around a lot in my sleep. I am leaning towards the Ultralite or Alpinlite. Would rhe short be too short for me? I don't want my bag to be less efficient i.e. cold if I go with the regular and end up with 5 extra inches around my feet. Wondering the same thing about the Alpinist vs. Ultralite in terms of wiggling around at night. Purchasing for my upcoming PCT hike. Thoughts? Thanks!

Kendall, Good questions! IF you are ok with it being a little short, 1" to be exact, then go with the 5'6". it will be a little tight, but just a little. The Ultralite is NOT the bag for you, though, if you are like me: a wiggler! Absolutely go with the Alpinlite, hands down. The Ultralite is very narrow and efficient, but not much room to move around if you are a wiggler. Hope that helps! Leta Western Mountaineering Rep

>Rating:

The price? I have been wanting the WM UL for a while now but it is just too much money for me. Will these sleeping bags ever be on discount?

Hi there - are you asking what the price is? If so, it depends on the length. If you are wondering why it's priced where it is, it is absolutely one of the best made bags, period. AND it's made in San Jose, CA... The production of these bags is limited, as is its distribution, so they never have excess, and there is no reason to discount. I hope there is a way for you to get into one of these bags! You will love it. Hit me up with any questions. Leta Western Mountaineering Rep

>Rating:

I'm 5'11", slender build, should I go with a 6' or 6'6" sleeping bag?

Hey Nate, I'm 6'2" and bounce between long and regular bags. I've found that since I sleep on my side often in warmer weather I can use regular bags but when I sleep on my back (usually in my winter bag) I need the length. So if you typically sleep on your side a 6' should be fine

Hey Nate - I agree with Reid, the 6' bag should be fine for you. I am 6'1" and sleep on my side and tend to prefer a 6'6" bag for the extra room. Feel free to contact me directly with any additional questions. - Kyle L. - Expert Gearhead

>Rating:

Would this bag work in summer as well as winter? Also, is it waterproof or would I need a waterproof bag to put it in?

Hi Sharon, thanks for writing. The Ultralite is awesome! 20 degree is a great temp for most seasons, but the great thing about this bag, and other all other bags from Western Mountaineering that are greater than zero degree in their temperature: It has continuous baffles. What does that mean? Well, you can move the down from the top of the bag to the bottom of the bag by sliding it around to the bottom. This will give you less down on the top for when the temperature is warmer outside and you do not want to over heat. Does this make sense? Very cool design. Now, about the ultralite: It is a narrow and efficient bag. "Efficient" in that you are not wasting energy heating up dead space in the bag. BUT... it's too narrow for me. I love the 20 degree option, but for something more roomy and comfortable to move in, please consider the Alpinlite or Terralite from Western Mountaineering. Those are 20 and 25 degrees respectively, and have a bit more room, if you would like this. About waterproof, no. Are you sleeping without a tent? If you are out in the elements in this bag, it will get wet. So you need to have a tent or a bivy sack. Most important for us in this bag is your comfort. Your body needs to "breathe" and when you have a waterproof barrier to the bag, not only is it far more expensive, but it is clamier (is that a word?), and hotter. We do make bags in Gore Windstopper, not technically waterproof, but very close to that. Those bags are best for cold wet environments. What is your situation where you will use the bag? Where do you live? I hope this was helpful. Please reach out to me in the Backcountry Community if you have any other questions! Leta Western Mountaineering Rep

>Rating:

Anyone have thoughts on AlpinLite vs UltraLite for a 5-6 ~130lbs female, side sleeper? Do girls find the UltraLite too snug because the're not shaped like a carrot? Anyone have issues with dampness/wetness with this bag?

YES!!! I am NOT shaped like a carrot! It was too snug for me. For a side sleeper, I would definitely go AlpinLite. Thanks for the question! Leta Western Mountaineering Rep

>Rating:

The degree is 20F. What does that mean? Feedback much appreciated!

Kun, The 20F temp rating means that Western Mountaineering has built this bag to perform down to that temperature. Shoot me an email anytime you have questions! Jared D. Expert Gearhead 801.736.4336 jdowns@backcountry.com

>Rating:

Why do you not show normal metric weights and measures. They would be a help for anyone outside America as that is the only place using old measures these days. The vast majority of UL hikers are metric familiar as "gram counters".

Here are the specs in metric

>Rating:

Trying to decide between this or the WM Alpinelite 20 degree bag. Can't really tell what's different. Looking for something that's 3 season, light/ultralight and good for back AND side sleeping as I sometimes roll around. Is the only difference that the Alpinelite is a little roomier? Feedback much appreciated!

Hey Cri, You nailed it! The two bags are pretty much identical except that the Alpinelite is a roomier cut. Feel free to hit me up with any questions or if you'd like to place an order. Ben brabinowitz@backcountry.com 801-746-7564

>Rating:

which outer material is used on this bag? on web page it says Extremelite but i can not get any info how water resistant is this fabric. How does it compare to Pertex Endurance? Can you tell me how much g/sm? Thx

>Rating:

Does "right zip" mean the zipper is on my right hand side as I'm laying in the bag?

Hey Robert, Leta here with Western Mountaineering. It does eaxctly. Some people don't care which way, but if you are right handed, it's a bit easier to zip up and down when the zipper is on your left side, as you reach across your body. Hope this was helpful! Leta

>Rating:

Can someone please post a picture of this bag compressed next to a Nalgene for comparison?

>Rating:

Will a 6' left zip together with a 5' 6"...

Will a 6' left zip together with a 5' 6" right? If so how does that work? Are the zippers actually the same length and only the tail of the one bag longer? Thanks

Howard, My wife and I try that same setup, but with a regular right and a long left zip configuration. The bags mate well (assuming similar zipper size and type), but there's a large gap between our shoulders where her zipper ends and my bag extends a few extra inches. This creates a bad draft, and cold spots. The foot of my bag also reaches a little farther than hers, which is expected. The positive side is that it gives both of you a little more room to move around, and keeps the bags in place if you turn in your sleep. It isn't advisable on nights getting down to the bag's rating though, because of the mismatch.

>Rating:

Can't decide on the ultralight or the...

Can't decide on the ultralight or the alpinlight. I am skinny - 6-2 150 pounds and am worried the girth of the alpinlight might be too much. However the extra room may be nice for layering and room to move around. Any suggestions?

Your worry is well founded. If the bag is too big you will have dead space that needs to be warmed. On the other hand, if you feel like you prefer to layer and have room to move around and can live with the extra space, the the Alpinlite might be a good way to go. Best of luck!

I am in the same boat. I am just under 6 feet tall and my current bag claims to be 62 in shoulder circumference and I am worried about the ultralite bag being to tight.

>Rating:

I am 5'7 could i fit into the 5'6 bag or...

I am 5'7 could i fit into the 5'6 bag or should i just go with a 6 and put some clothing at the bottom to fill in the gap?

Go with the 6'. If you are too big for a bag, you will over-compress the insulation and lower the temp rating.

>Rating:

I'm a petite female looking for my first...

I'm a petite female looking for my first down bag after borrowing a friends' and loving it. I swore I'd never camp again with temps under 25 degrees with my current bag.... would the ultralight be warm in temps down to 15? What temp bag should I actually be looking for? These temp ratings can be confusing! I'm like a lot of women...cold feet, hands, cold everything.... I'm also interested in a bag that packs light and small..this thing goes with me on my bike, suitcase, and whatever couch I might be crashing on.... Thanks for any advice!

If you cold take the warmes sleepingbag you can take. The EN rating is what you lokking for. it said women r cold and need a warmer bags...dont go by the US raiting, you get cold I hope it's help (:

Disregard what Guy said--EN ratings are good for comparing different brands of bags but don't give you an accurate temperature that you'll be comfortable in. Western bags are over filled and conservatively rated. I have slept in a 25degree Western sleeping bag in 25degree weather and I was perfectly warm and I get cold easily. The key is the amount of down put into the bag. Not only does Western use the highest quality European goose down they can get, they then put large amounts of it in the bags. I'd trust the temperature rating with Western Mountaineering bags. The average person would be warm 5 degree below the rating, but if you are thinking you'll regularly experience below 20 degrees AND you run cold, I'd think about the Versalite for a couple ounces more. You could also get a sleeping bag liner that would boost the temp rating on the trips you think temps would be colder than 20. Hope this helps...

As far as EN ratings go- I have never, ever found any sleeping bags that have met of exceeded WM's in accuracy. WM has never let me down and cost me a single night's sleep because I was cold....the only problem is not wanting to get up in the morning.

Western mountaineering bags are indeed conservatively rated. If you look at a UK site, you'll get the EN ratings (EN is required in europe I believe). Over in the EU the Ultralite is billed as a 16F bag rather than a 20F as in the States. I think they refrain from quoting the EN rating because they have built a decades long brand on their old conservative ratings and want to maintain reliability from year to year over marketing hype (even if it is in their favor). http://www.elitemountainsupplies.co.uk/product/954_western-mountaineering-ultralite-regular-sleeping-bag.html

>Rating:

Why is there no Left Zip option for the...

Why is there no Left Zip option for the 6ft bag?

When Backcountry runs out of a certain item, it disappears from the purchase options. Left zip is available, but Backcountry doesn't have any right now.

>Rating:

im looking for a bag to use on my thru-hike...

im looking for a bag to use on my thru-hike next year on the PCT, and its a toss up between this and the apache. is the couple ounces of weight worth sacrificing the durability of a regular WM bag?

Having used Pertex in both bags and jackets for a while now, I can tell you that durability shouldn't be a concern. Unless you intentionally pull your bag through thorny bushes or slide down abrasive rocks using the bag as a sled, you'll be fine. Between the two bags, I'd be more concerned about fill weight. You get an extra 3oz of down in the Apache. That could make a huge difference on the PCT. If you decide to go with the UltraLite, call WM and ask them about having it overstuffed. Then, you can get the benefits of more down and keep the light weight.