Kappa Jacket

Versatile synthetic-insulated jacket with hood and chest pockets. Primaloft Gold-fill. Perfect for most active cold weather sports. Available in custom sizes.
Typical Operating Temperature
Guideline minimum temperature. Sleeping Bag TOT: you should get a night’s sleep, under normal circumstances. Clothing TOT: you should feel warm enough, assuming low/moderate activity. Sleep System TOT: relates to full system. For more details, see our Technical Briefing.
-10°C / 14°F
For clothing, weight is for size: M. For sleeping bags, weight changes with selected length/width. N.B. there may be some variation in the weights of finished products.
650g / 23oz
Kappa Jacket

I've worn this jacket for the past nine months ... Despite being very lightweight it really is bombproof.
Adele Pennington, AMI instructor and Expedition Leader for Jagged Globe, Trail Gear Guide.



  • Primaloft Gold® synthetic insulation (133gsm)
  • Outer Fabric: Waterproof Dri-LX (un-taped for lightness)
  • Inner Fabric: Superlight MX
  • Pockets:
    • 1 chest pocket - zipped
    • 2 handwarmer pockets - zipped
    • 1 inside security pocket - zipped
  • Velcro Cuffs
  • Elasticated draw-cord adjuster at hem
  • Reflector tap across chest & on zip tabs for night location
  • Fleece lined collar
  • Edge Stitched for maximum loft
  • Zip-off hood with cord adjustment and volume reducer tab
  • Hood reducer with Velcro tab
  • Stuff sac - 13cm x 21cm*
  • Options:
    • XS, S, M, L, LX
    • Custom sizes
    • Colours: red, green, white, black.


*Please note: We make our stuff sacs big enough to allow fairly easy stuffing rather than reducing the jacket to the tightest minimum.


Also available in custom sizes. We make clothing to order, so if you’re not a standard size we can make it to fit. To order a non-standard custom size, select the Custom Sizing tab, choose your body width, and then the body/arm lengths, shorter or longer, that work for you. A custom size takes us a little longer (typically two weeks longer) to make and, because it’s personalized, it’s non-returnable and our customer loyalty scheme can’t be applied.


Redesigned with chest reflect tape for safety and more colour options.

The Kappa is a truly versatile crossover jacket, completely at home on high Himalayan treks, Alpine ascents, Scottish winter routes or any active cold weather sport – one has already gone off dog-sledding in the Arctic, a function we didn't anticipate.

Excellent protection is provided by the Dri-LX waterproof outer* and quick body warmth by Primaloft Gold® insulation, which will retain much of its insulation when it's wet. It also works well when you're already soaked and simply want a warm-up jacket to shift the chill.

The Kappa's two zipped hand-warmer pockets make it a pleasure to wear round camp, while the two chest pockets (one out & one inside) provide plenty of space for camera and keys.

The zip-off hood adds significantly to warmth and protection in wild weather.

Insulation is Primaloft Gold® (133gsm).

Mate with our Kappa trousers for a complete system!

* - Please note: although the outer fabric is waterproof, the stitch lines are un-taped for lightness. So, although the outer will shed rain and snow, in a heavy downpour water can penetrate the stitching. However, the Primaloft insulation retains much of its insulation if wet. As always in the mountains, if there is a possibility of rain, carry full specification waterproofs.

Dri-LX (weight: 64 gsm)

At just 64gsm, Dri-LX is our lightest 2-layer breathable waterproof rip-stop nylon fabric. Its remarkably low weight not only makes for a lighter load, but also reduces pack size. Its excellent waterproofing qualities are in part due to how it can be taped at the seams to create a waterproof shell for sleeping bags and clothing.

Superlight MX fabric (weight: 32 gsm)

A mini-ripstop nylon with excellent tear strength, MX is the pick of the superfine 15 denier downproof materials. We have tested lighter fabrics, but most have had significant drawbacks, while our confidence in MX is based on several years of extensive use in both our ultralight and our high mountain gear.

Primaloft Gold®

Primaloft Gold® is the ideal microfibre insulation. Ultrafine fibres produce an insulating core that is incredibly soft, lightweight and water resistant. In our experience it absorbs water much more slowly than other waddings, a marked advantage in wet-cold conditions.

The nearest of the synthetics to the feel of down, yet tougher than you would expect. Primaloft Gold® offers the best warmth/weight performance in the Primaloft range

"I've worn this jacket for the past nine months and it's seen use from Scottish winters to Makalu in Nepal to the mountains of Kenya. It's been worn in all conditions, from rock- and ice-climbing to heavy snow. Despite being very lightweight it really is bombproof, and it has taken a lot of battering and scraping so far. The Primaloft insulation has kept me perfectly warm too."
Adele Pennington, AMI instructor and Expedition Leader for Jagged Globe, Trail Gear Guide.

"Very warm, very water repellent, seriously tough, unapologetically functional, all-round adjustable, zip-off hood. Pack size is reasonable too."
Outdoorsmagic review.

"[The Jacket] performed wonderfully, I skied and climbed and slept in it, and it was both warm and almost weightless."
Janey King (a.k.a. Rosie Thomas), British Shackleton Traverse over South Georgia.

"I took the chance to test the jacket today. I was very, very impressed with the jacket. In the more exposed areas or when travelling fast I could feel the coldness of the air pressing on my arms (not leaking through the fabric), but I never got chilled. It is hard to describe, it's a bit like holding an iced drink in your hand - you can feel the glass is cold but you don't get cold yourself.

The fit, especially around the neck, was loose enough to cope with under layers and balaclavas but never let in draughts either. Body length and sleeve length were good too - just about long enough to cover most of my backside and sleeves never got close to riding up far enough to expose my wrists etc. The hood and ruff work well too. It is plenty big enough to go over all my hat layers and the ruff did a good job of blocking the wind / catching the ice in my breath.

The outer fabric is really amazing. I was a little concerned that the membrane would limit breathability and that it might go stiff and feel almost brittle like some Gore-Tex fabrics can in the cold. No such worries here! It remained loose and soft to the touch even at -25C. In the wind it would flap about quite happily and shake off any ice build up. I'm also guessing this action might have helped pump out moisture from inside - I certainly never felt damp or clammy, even if I was skiing harder.

I really appreciated the fact that the outer is almost a separate jacket and it is not stitched through to the insulation. This seemed to add a whole new dimension to its protection, warmth and weather resistance. This is a very, very good jacket.

I've owned many over the years but I have never had one that can cope with such a variety of awful conditions, that is this warm and light but that does not sweat up inside either. This combination of fabrics, insulation, cut and fit is as near perfect as I can imagine. It stood up well to both the elements (down to -25C) and physical wear and tear very well indeed."
James Garrett testing the Kappa Jacket ski trekking and snow shoeing in Finland.

Works well with
From £373.00 475g -10℃
Our warmest synthetic-insulated mountaineering trousers. Waterproof fabric and...
From £164.00 150g
Primaloft-filled mountaineering mitts. Confidence and warmth in cold and wet conditions.