Friends, Family, Countrymen... to truly perfect this great piece when the temps are sub 30's layer like this; baselayer = merino wool / capilene / polyester / etc., Midlayer = MontBell UL Thermawrap. Now if you have a hardshell make sure you have another barrier over your Thermawrap because as I found out the hard way when going fast and hard and pumping sweat, there was too much body heat (condensation) on the inside of my shell so whenever the winds blew, I was uncomfortably chilly. To fix this, put another wicking layer over the Thermawrap and your hardshell and your body heat will dissipate just fine and you can tell the wind to kiss your ass. What can I say that hasn't already been said by others? It is super light, it is surprisingly durable, it does block about 87.349% of the wind, and finally, keeps me warm when stopping for a break on the trail and I've drenched this piece in my sweat. Very, very nice!

Upon seeing the 3 thumbs down, I had to reassess my review and look at what negative factors contributed to a misunderstanding or dislike of this article. It could be that my review just wasn't technical enough so let me try...

This jacket only has two front hand pockets which are not fleece lined or zipped. It has an elastic waistband that does fit snugly around your waist if you are even a hair overweight. The only zipper is the one on the front that goes both up, and surprisingly, down. It is extremely packable, stuff sack is probably 3.5"x6", but even when in it's stuff sack in can go smaller if needed to. It cuts decently through the wind, give it a 4 out of 5 stars and has no factory DWR applied to it so the 15D material gets wet very easily. In bitter cold, (0-20 degrees F) do not expect this to keep you warm if you are not moving. You will get hot while moving if the temps are (21-+ deg. F) It could afford better stitching so it would last longer. It feels super light, slightly cheap, but it's from the no extras added design. Once again, super packable.

I've only owned the jacket for a week or so, but I've found myself wearing it every day during this cold fall. Very comfortable and extreemly light weight. Nice replacement for a bulky sweatshirt. I've found it to be pretty windproof. It does fit tight. I'm 5'7" 150lbs and I got a small. It is very snug and fits like a shirt. The nice part about this is it will be great for an underlayer.

Overall, I'm very pleased with this product.

Purchased this as an alternative to my heavy-weight TNF Windwall fleece. It is easily as warm, but is less bulky, weighs nothing and packs to the size of a tennis ball. I layer it over a lightweight shirt and under my soft shell. It has kept me comfortably warm sitting on summits at sub-zero temperatures in heavy wind. I'm 5'10" 165lbs and ordered a medium. Fit is a little baggier than I was expecting, but torso and sleeve length are both long enough to retain coverage during high reaches. As an "ultralight" garment, you have to accept the decreased durability. I'm cautious to wear it as my outer-most layer, and the collar lining is showing wear. That being said, I would highly recommend it.

So Climing Mt Dickerman in the PNW and get to the summit and see this guy in this uber light jacket in its tinsy winsy stuff sack. I had to ask, then I had to get one! Works PEFECT under a Mammut Ultimate Hoodie with a smart wool top under that. Toasty warm and light. Can you say smart summiting. I knew you could. I was so light I thought I would need a string tied to my ankle!

Super light, super warm. It will get burned next to a poppin fire though. My all time favorite piece of gear.

I don't go out without it--It's so much lighter than my previous go-to fleece midlayer/light outer layer. It's definitely a no-frills jacket--it's obvious that MontBell made design choices based on WEIGHT and not FEATURES. The pockets don't zip and aren't lined, the elastic wrist openings are not adjustable, but I don't care. It's totally cozy and it's always available because I can't make any excuse not to carry it. I bet it would really get destroyed if you got too close to a campfire, though. I don't do fires when I backpack, so I'm not concerned with that, but you might factor that in.

I have had this jacket for several months. As the weather has become progressively colder, I have noticed that my jacket has always kept me warm. I think the coldest weather I have experienced with this jacket is 14 degrees F plus a wind chill. I stayed warm with just a long sleeve shirt underneath!

The best part is how incredibly lightweight it is. I haven't used it in the back-country, but I suspect it will do an excellent job.

Light, Check! Warm, Check! Stylish, Check!
So I tried this on and then slapped on a Mammut ultimate Hoodie. THE PERFECT combination for living in the PNW! Warm and dry!
The new design brings some much needed elasticity to the waist and the cuff. This is by far my favorite jacket! I love it so much I am going to get the vest!

Warm, light and comfortable. Packs small and relofts quickly. Good jackt for end of the day lounging in the summer and all day use in fall, winter and spring. I only worry about the durablity of the fabric when its worn as an outer layer. It hasn't yet, but seems like it might rip easily, although knock on wood, after a month working in the field it is still holding up.

This jacket is amazingly light and stops the wind cold! I love it. I find myself wearing it everyday instead of my sessions shell! You gotta try this!

I wanted a warm insulation layer that I could hike in and that would be nice and toasty in camp or during a lunch break. I find down too stressful to wear, I'm constantly worried about moisture from my sweat or an unexpected shower or what-have-you, so after some research I settled on this jacket.

As an ounce-counter, I find the weight of the jacket to be fantastic. It isn't as warm as I had hoped, but that is more a problem of my own expectations than the product itself. In the end, it works better as an ultralight fleece replacement than as a "puffy" for very cold situations.

If you need something really warm, look elsewhere. But if you want an insulation layer that's great on-trail, still useful wet, and lighter than any fleece, this is exactly what you're looking for.

My husband was looking for a lightweight warm jacket for those spring bike rides. This jacket has fit the need exactly. It's a good wind barrier with excellent warmth. He felt the cuffs needed elastic, but that was his only complaint. The fit was great.

"170#, 5'8" athletic: I got the medium, it was a little short and wore like a shirt, but the real problem was the arm pits fit very tight, too tight for adequate mobility. Will size up to a large and see what happens. Lost star for fit."

Sized up, and had perfect fit. No further complaints, great piece of gear.

I work at a high-end gear shop in AK, so I see a lot of technologies come through, but this is one of the best layers I have encountered. I carried one of these on my 2 week backpacking adventure through the Brooks range, and used this thing constantly. We get really mixed weather in the Brooks in the summer, everything from snow flurries to 70's and still. This jacket lived in the top pocket of my pack. I put it on for wind, light precip, snow, and rest stops on chilly summits. I use it as a major part of my winter layering system too. Excellent ice climbing belay jacket, backcountry skiing layer, and all-around insulating layer. It doesn't weigh anything, packs into the top pocket of my pack, blocks the wind, holds the body heat right next to you, and dries in minutes. pure magic!

Great Jacket- Light, stylish and fitted. Unfortunately, I couldn't justify the warmth v. cost. It's not super warm, and better suited to aerobic activity. It's about as warm as a fleece while only half the weight. If you can afford a light insulation layer, book it. If you're on the edge, consider the redpoint or some other primaloft jacket.

The five star reviews are accurate. This is essentially the next iteration of the fleece, i.e. it is lighter and compacts much easier than the fleece. Keeps ya warm and will repel light rain (haven't been soaked in it yet). Definitely great to have in the arsenal.

170#, 5'8" athletic: I got the medium, it was a little short and wore like a shirt, but the real problem was the arm pits fit very tight, too tight for adequate mobility. Will size up to a large and see what happens. Lost star for fit.

Gearing up for a pack in high country bow hunt instead of our usual base camp hunt. I was pleased to have the choice to purchase a women's jacket. So many times there isn't that option. Then I started second guessing ... men's vs women's. Opted to purchase a men's jacket hoping I would get extra shoulder room to be able to draw a bow and more layering possibilities. (Practicality wins over fashion in my book.) Very pleased with the cut and the pack size! Immediately ordered one for my hunting partner. This jacket has already earned a spot on the must have gear list.

Pockets lack zippers. Waist lacks draw cord. Too bad, this could be an ideal jacket but it lacks these two obvious (to me) assets.

This jacket is way too light,I can't believe how light it is. it looks cool and you will need to wear something underneath it to provide the full wormth.