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Mountain Hardwear StretchDown DS: redesigning the concept of feathered insulated jacket.

If you have been following my adventures through the summer, you have probably seen me constantly with the new Mountain Hardwear StretchDown DS jacket. When I saw it for the first time this ISPO, it’s concept, fit and technology made an impact on me. It is incredibly eye catchy with it’s discontinuous panel welded technology. You want to touch it and indeed It is incredible it’s ability to maintain the air chambers, the density of them and the robust feeling that you get.

Once you put it on, the padded feeling is still real and unaffected by the achieved ergonomy and stretchiness of the fabric. On the other hand, it is not extremely compressible, neither ultralight and I still didn’t knew how it was behaving against abrasion in technical activities. My colleagues from Mountain Hardwear Spain, approved that those seemed like leggit questions and that we should make that jacket earn its reputation in my favorite playground: my Norwegian Summer. Over here we may bake in the sun, belay in july at 12º on a raging atlantic storm, snowing in the high mountain in august, under a constant rain on long hikes and every now and then seeking that bivouac spot mid september when temperatures in the night down the valley can drop to 5º.

Last week Mountain Hardwear released the first teasers presenting it’s new technology.


For testing StretchDown Ds as outer layer, i’ve been using it with a technical t-shirt under, Let’s see how it performs in different conditions.

For moderate intensity activities: such as casual hiking, it’s ideal conditions are with temperatures around 12º. Regarding wind, it work extremely well against moderate to strong wind. The truth is that wind has little effect on this fabric as it has very little ability of going through it. Best conditions will be a chilli and dry day, but it does the job as well on moody days with higher humidity in the atmosphere and even under light rains.

For moderate to intense activities: such as fast alpine hiking, It’s ideal conditions are cold and dry days with temperatures around 5º to 7º.

Waterproofness:The StretchDown DS fabric has a certain ratio of water repellant and it really has it. It is not one of those claimed water repellent fabric that has a life expectancy of five minutes under light to moderate rain. As any kind of feathered insulated jacket, rain is very far from been it’s comfort zone. In fact if we are expecting proper rain, the best is to leave home any kind of feathered fabric. However, living in westland Norway, been caught under unexpected heavy rain is something that pretty much happens weekly, if not daily.

In activities up to four hours with with occasional light to moderate rain, this jacket do the job as outer shell. Conditions on the atlantic coast are very changeable and moody days are the status quo. Our light rains tend to last around fifteen minutes and the sun or the wind comes. When those are the conditions, the water barely wets the outer layer. It definitely does not make its way to the core of the fabric, neither to the feathers and neither to you and then it dries extremely fast when exposed to the wind or sun.

Under short intervals of moderate rain, the structure of the jacket stays on place. The core does not get wet, moreover the air buble and the thermal insulation are still effective. That’s impressive for a feathered insulated jacket. In these conditions you can tell the difference in the quality of the fabric with some other down jacket technologies in the market. As soon as they get some water on them, it seems like the whole structure is melting and they not only stop generating heat but they start to take it away from your body.

There is a last important point to make for those moody days. When rain starts, generally the wind stops, the humidity raises, the ambiance become more charged and the temperature raises. As I said, in those conditions perhaps the jacket may resist well the rain for some time, but if you are on the move you will most likely start sweating big times inside the jacket.


I have also been taking this jacket lately as mid layer on hikes of around four hours that I knew we were facing prolonged moderate rain with proper heavy showers in between with temperatures around 10º. As outer layer I was using a long waterproof trench coat. To be fair, I’ve been incredibly surprised that the combo worked and that the midlayer did not absorbed more water during such those days.

Don’t get me wrong, going to the mountains on those conditions sucks, mid hike you already feel your feet completely wet despite your  gore-tex boots, your hair is soaked, you feel kind of wet, warm and cold all over at the same time and the outer skin in your hands feels like it’s about to fall after the third hour.

However in such situations when i’ve reached the top and started to get ready for turning around while do all the pertinent changing of layers and clothes needed, I’ve realized that the StretchDown DS has hold surprisingly dry under my trench coat. I think one of the key points is that the trench coat is wide, so water can glide over it without necessarily getting so much in contact with the fabrics under, kind of like the effect you seek on a two layer sleeping tent. The area of the back always gets more wet as a blended result from my sweat, the heat and friction coming from the backpack and the water gliding closer to the fabric. The area around the armpits also gathers moist, primarily as a result of my sweating, but for the rest it remains pretty much dry.

In fact the two last times that I’ve had these conditions, on the top I’ve decided to remove my technical base layer, as It was absorbing more sweat and moist and just put as first layer the StretchDown Ds and over the waterproof trench coat. As a matter of facts, both times I’ve done this, I’ve made it down on more ideal conditions of heat and dryness than on the way up. However that comparison is tricky because hiking down I always sweat less and use less effort. Moreover on the first hour of the hike is when you are still not warmed up, so you have quite some clothes on and at the same time when we tend to find the strongest uphills and when I tend to sweat the most.

Even though I got impressed by the endurance of the StretchDown DS in wet conditions, a feathered insulated layer should not be our first options for wet conditions. As I pointed out, under proper rain, using it as a midlayer under a real waterproof jacket during a four hour hike is as far as I would take it, even though it has done the job properly three times. If water goes to the core of a feathered jacket, it will not provide any more any kind of insulation. In fact it start  taking the heat away from you. Many down jackets, once they got wet to the core, the performance of the fabric can be seriously damage and even destroyed.


It is not a base camp jacket. It is warm and solid enough as to be comfortable on a cold belay stance during the three seasons. You will as well feel comfortable while eating, resting, cooking or doing any kind of stop during the activity for a maximum of two hours at around 10º, but if you are looking for a jacket for doing the cooking and hanging around during the nights in the base camp in the fall, where temperature can go under 7º, then you will need a proper base camp down jacket or reinforce the StretchDown DS. That’s perfectly fine, actually Quite often I combine it with a merino wool baselayer under, a light technical activity layer of primaloft with a light feathered panel on the front or I just put over the Heritage pile Jacket by Helly Hansen that I was testing last summer. With both jackets you literally feel inside an oven, but that’s only possible if the second jacket is left on the car or on the base camp. If I have to carry both in my backpack I will need a thirty litter backpack just for both jackets.

At the same time that it’s not a base camp down jacket, it is neither an ultralight and hyper compressible technical layer. It is not a Mountain Hardwear Ghost Whisperer, neither a North Face verto micro hoodie, neither a Patagonia micro puff. However this proposal by Mountain Hardwear covers an extremely wide spectrum in between and that’s something new and exciting in the classical proposals of layering systems that we’ve been witnessing lately in the market.

In terms of stretch, ergonomy and dinamism, the StretchDown Ds overperforms largely some of the best contendants of the category ultralight technical insulation. When it comes to compression and weight, then that’s a different story. The StretchDown DS takes significantly more space and weight on the backpack. More or less, it takes around half of my 16l backpack. However with the StretchDown you have a real jacket. Real insulation and a wide range of situations where it can work as your shell.

When it comes to compressibility, it doesn’t really matter for some activities. For example, it looks like I will use it very often as my midlayer in winter for ski freeriding days on the resort, where it will be for the whole activity on me. However, when I go to the high mountain or wall climbing, then space and weight are key criteria. This spring and summer it’s been incredibly good and warm weather in Norway and to be truth, most of the times I was rather leaving the StretchDown DS on the car and put on the backpack something less solid but more compressible. However this time of the year, when it is getting proper cold from 19.30 on, it’s starting to snow on the high mountains, weather is getting moodier and nights longer, then I stubbornly always carry it with me on my backpack. In Norway you shouldn’t joke around with the exposure and the weather in the wilderness. Well, you probably shouldn’t do it anywhere actually.


Mi last highlight goes to the design. I personally really appreciate that it is a technical layer for the high mountain, but at the same time elegant. Even at first sight you get instantly charmed by its ability to keep the volume, the technical finishes, the discontinuous panel welded technology, even the colours of the range. People approach you to feel it and ask about it. Such magnetism is achieved on a very humble way; without going for massive logos, shiny colours or plastic-like finishes. In my opinion that’s an extreme success.

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