Mountain Equipment Kryos Jacket Review

© Dan Bailey

Very warm for its weight, the Kryos boasts a construction that maximises weather protection while limiting bulk, making it an ideal down jacket for active use in colder conditions. It's developed, say Mountain Equipment, for cutting edge alpinism. But while most of us can't claim the same, the features aimed at fearsome faces, spindrift-raked belays, and precarious bivvys on tiny ledges will prove just as welcome on the more modest hills of home. Even very average winter mountaineers are going to appreciate such a well-thought-out and thoroughly field-tested design. At this price it will be a considered purchase, but quality simply doesn't come cheap, and the Kryos should offer years of reliable service.

I'm in for a cold night, but the Kryos should see me right...  © Dan Bailey
I'm in for a cold night, but the Kryos should see me right...
© Dan Bailey

I've had a Kryos on long term test since last winter, and though Coronavirus curtailed my climbing season, it saw active use on snowy and windy Scottish hill days, and sub-zero camps. I liked it so much that I almost lamented the coming of spring. With cold season nearly upon us again, with a Kryos in my cupboard I feel well set for any icy blasts heading our way.

Weight and packability

For easier packing the jacket scrunches into a stuff sack that's something like twice the size of a 1-litre bottle - not tiny, but compact enough considering the performance you're getting. While there's a tag to hang it off your harness I think it's a bit bulky to do so (and on a big winter route I'm not sure I'd trust the hang loop with £400 of essential insulation).

For its warmth, it packs down reasonably 'small'  © Dan Bailey
For its warmth, it packs down reasonably 'small'
© Dan Bailey

On my kitchen scales, generally pretty accurate, I make it 618g in size Large (ME say 610g), plus a further 11g for the stuff sack. In terms of winter mountain down jackets I guess the Kryos sits on the scale somewhere between the midweight and full-weight categories. While it's not an absolute beast for polar adventurer types or very high altitude, it arguably strikes a more versatile balance of warmth:weight:packability for mountaineering in some pretty hostile temperatures.


The Kryos comes in both male and female-specific models. It's not always that women get the option of top end technical clothing that's actually made to fit them, rather than having to settle for an ill-fitting men's version, so well done Mountain Equipment.

It's well suited to colder UK winter hill days  © Dan Bailey
It's well suited to colder UK winter hill days
© Dan Bailey

Low rear hem gives good bum coverage  © Dan Bailey
Low rear hem gives good bum coverage
© Dan Bailey

A generous cut accommodates several layers underneath. There's enough length in the body to keep out draughts at the waist, and a drop hem at the rear that gives almost full bum coverage for maximum snugness. In my experience few down jackets are that effectively tailored for moving in, being more intended for hanging around on belay or at base camp; but the Kryos has a genuine active cut, offering free arm movement and, on me at least, only negligible hem lift when the arms are raised. While I've only walked in the Kryos as yet, I'm confident that I could climb in it quite happily too, should the need ever arise.

Big sleeves fit easily over bulky mountain gloves, and while there's no tab to tighten the fit at the wrist I've not found that one is needed since the simple elastic cuffs give a close enough fit to keep out the elements.


Packable warmth is the name of the game, thanks to 800 fill power 90/10 goose down with a luxurious high-lofting feel. In size Large there's 234g of fill, so in typical UK winter temperatures you're going to struggle to get cold in this jacket. I've worn it very happily hanging out all evening on a high snowy camp at around -5 (assuming the forecast was accurate); and on windy Scottish summits where the temperature was definitely some way below that it's kept me very toasty. As yet it doesn't feel as if I've got close to the lower limit of the Kryos, and if I were anticipating extreme cold in the minus double digits then this is the jacket I'd pick from my gear stash.

Baffles inside, extra layer outside  © UKC Gear
Baffles inside, extra layer outside
© UKC Gear


Inside a down jacket the fill has to be held in sections, or baffles, which stop it migrating around to create cold spots, and give the down maximum freedom to loft and keep you warm. The traditional choice is between stitch-through or box wall baffles. The latter should be warmer, but they also add expense, weight, and bulk, making for a jacket that feels comparatively cumbersome to move around in. Stitch-through baffles may be cheaper, lighter, and simpler, but all that stitching will let wind and weather through. The Kryos neatly solves this issue.

Here the baffles range in size and shape, with smaller stitch-through baffles on the hood and arms that allow for greater mobility and less bulk, and larger pleated baffles in core areas that need more warmth. But it's what's outside that really counts. As used on the Kryos (midweight), Xeros (lightweight) and Exo (heavyweight), Mountain Equipment's 'Firestorm' construction wraps the baffles in a separate outer layer. Made of weather resistant Gore-Tex Infinitum, this drop outer features minimal exposed stitching, protecting the insulation from moisture, creating an effective barrier to wind, and adding an extra layer of trapped air which, say Mountain Equipment, boosts insulation performance for only a modest increase in weight and bulk.

It's great for winter hillwalkers on windy Scottish summits, as well as alpinists with bigger fish to fry  © Dan Bailey
It's great for winter hillwalkers on windy Scottish summits, as well as alpinists with bigger fish to fry
© Dan Bailey


Gore-Tex Infinium combines a light-but-tough 10D nylon face fabric with an EPTFE membrane. It's the same idea you'll find in Gore-Tex shells, but in this case it's tweaked more towards breathability than out-and-out waterproofness, giving you a fabric that's comfortable to wear on the move while still offering higher levels of wind and weather resistance than you'll typically see in a duvet jacket. In biting wind and billowing spindrift I'd generally think about adding a shell, but on the occasions I've been out in such hostile weather in the Kryos I've felt well cocooned from the elements with this jacket alone. I'd argue that its weather performance gives the Kryos a bigger potential niche in the UK winter hills than many down jackets, and on the right occasion it could well find a role on a winter belay or a bivvy, in preference to the more orthodox synthetic alternative.

The face fabric will shrug off moisture with ease, be that rain or snowmelt, and while I wouldn't choose to test it in a downpour, that's not the sort of weather you'd want to be wearing something this toasty in anyway. As well as creating a weather-beating outer, the same fabric is sensibly used inside the hood and collar, down the rear of the zip, around the inner hem and up into the cuffs - the places where moisture is most likely to creep in over a long day.

The main thing for active use is that it's also very breathable. Whether you're climbing hard on some icy horror or, in my case to date, plodding uphill on a frozen Munro, I can't see the fill wetting out from excessive sweat in a hurry.

Loving the snug hood and high collar  © Dan Bailey
Loving the snug hood and high collar
© Dan Bailey


If you like pockets, you're in luck here, with two big chest pockets - plenty of space for a phone or bulky gloves - and a pair of generous hand warmer pockets; all feature robust YKK Vislon zips. Inside are two large drop pockets, which are a good place to defrost frozen gloves or keep your rock shoes warm if winter bouldering is your bag.

The main zip is another chunky YKK Vislon, backed with an effective draught excluder and featuring a double zipper for easy harness access when wearing the Kryos as a belay jacket. The hem drawcords can be easily operated wearing gloves, and they are Mountain Equipment's usual dual tether design that won't snag on gear racked on your harness.

It's got chunky zips  © Dan Bailey
It's got chunky zips
© Dan Bailey

And handy inner drop pockets  © Dan Bailey
And handy inner drop pockets
© Dan Bailey

Another thing we've come to expect from the brand is a really decent hood, and the Super Alpine HC Hood on the Kryos doesn't disappoint. Sized to fit over a helmet, it won't much limit head movement even with the zip done up fully. The volume can also be cinched down via a velcro tab at the rear and two drawcords with adjusters concealed in the rim, to give you a pretty snug fit on a helmet-free head.

To save you from being whipped in the eye by the tethers in a high wind, the drawcord tails exit the jacket quite far down. In stormy conditions you don't have the benefit of a stiffened peak to help the hood hold its shape, but I guess it's a fair assumption that most users out on the move in that sort of weather are going to be climbing, in which case the helmet will give the hood its structure anyway. When a hood isn't needed, the collar sits high, offering loads of protection to the neck and chin.


Far more than just a footnote, the environmental, human and animal welfare costs of outdoor gear should be among our primary concerns as consumers. Many brands are taking steps to reduce their impact. Mountain Equipment subscribe to the Down Codex scheme, which provides an auditing trail to ensure that the down they use has been produced to meet certain standards of animal welfare. They are also members of the Fair Wear Foundation, which works with brands to achieve fair(er) working conditions worldwide.

Mountain Equipment say:

Developed for the cutting edge of Alpine style climbing; the optimum combination of warmth, protection and minimal weight.

Informed by feedback from some of the world's best Alpinists and extensive R&D work this is the jacket for the hardest and most committing lines in the high mountains. A GORE-TEX INFINIUM™ drop outer provides proven additional warmth and weather resistance whilst the Super Alpine Hood gives unrivalled protection.

  • Sizes: S-XXL (men) 8-16 (women)
  • Weight: 610g (ME's figure)
  • GORE-TEX INFINIUM™ 10D shell is durably weather resistant
  • FIRESTORM™ construction for greater warmth, wind resistance and weather protection
  • Hybrid baffling combines both conventional stitched-through and pleated baffle construction
  • 234g (Size L) of Goose Down with a minimum content of 90/10 800 fill power
  • Super Alpine HC Hood
  • Halo collar
  • 2-way YKK® moulded centre front zip with lightweight offset rear baffle
  • 2 zipped hand warmer pockets, 2 chest pockets, 2 large inner drop pockets
  • GORE-TEX INFINIUM™ 10D hem, cuff, and hood lining
  • Elasticated cuffs and dual tether hem drawcords
  • 100% Polyamide outer/inner

For more information

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