Denali Down Trousers 'K Series'

Superlight high-altitude mountaineering and polar down trousers for light ascents and quick travel.

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.
-38°C / -36.4°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.
430g / 15oz
Denali Down Trousers 'K Series'


  • A PHD K Series product: Ultimate warmth / weight ratio
  • PHD's Unique 1000 fillpower down
  • Water-resistant Ultrashell outer fabric. An excellent balance of weight, water-resistance and breathability
  • Superlight 10X inner fabric. Down-proof, wind proof and super soft
  • Box-wall construction for maximum loft
  • Side Zips:
    • Full length
    • Two way (join at the top)
    • Insulated under-baffle
  • Waterproof HS2 fabric reinforcement on the knees and the bum
  • Elasticated waist with adjustable shock cord hem
  • Stuff sac
  • Pack size 17 x 28cm
  • Options:
    • Waterproof Dri-LX taped outer shell (adds 150g, +£105). Available in red, green, black or all white.
    • Custom sizing for a perfect fit

* Please note: we make our stuff sacs big enough to allow fairly easy stuffing rather than reducing clothing 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 and choose the waist and inside leg sizes 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.

The Denali Down Trousers are designed for high altitude mountaineering and fast polar expeditions. These incredibly warm and light, full-length down trousers give substantial protection in the most inhospitable locations. 

Filled with exceptional 1000 fill-power down, and made in our lightweight water-resistant Ultrashell fabric, the full-length side zips and the added protection of waterproof HS2 fabric on the knee and the seat make for a robust and superlight package.

The combination of the Denali Jacket (725g) and the Denali Trousers (430g) used together (1155g), makes for an exceptionally light & flexible high altitude or polar set.

To make the trousers easy to put on and take off, we have used full-length, 2-way side zips (separating at the waist) with Velcro lock tabs to hold the trousers up while joining the zips. No braces to complicate the act—they are simply not needed in trousers this light. These trousers can be put on or taken off easily whilst wearing crampons or skis.

An optional, fully waterproof taped outer shell (in our Dri-LX fabric) can be selected to protect the down on long and arduous expeditions. The extra layer of fabric adds to the weight and bulk of the trousers but extends its use even further into a wider range of conditions.

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.

Ultrashell (weight: 40 gsm)

One of the lightest of PHD's coated materials. This ripstop nylon provides complete wind block and good water resistance at minimal weight. Ultrashell gives an excellent upgrade to performance with very little weight penalty.

Ultralight 10X fabric (weight: 26 gsm)

10X, PHD's first 10 Denier Fabric. 9,000 metres of the yarn used to weave 10X weighs just 10g, that's about the same as a £1 coin! For all its thinness 10X is amazingly downproof and with reasonable care will go on giving you good service for years.

1000 fillpower down

This rarest of all downs we reserve for the K Series. European goose down of unique quality. 1000 provides the highest warmth-for-weight performance possible from down. More on our down insulation.

Waterproof HS2 outer fabric (weight: 88 gsm)

HS2 is a 2-layer laminate, a high-spec option for the outer layer of our insulated gear. This ripstop fabric strikes an excellent balance between lightness and durability. It is light enough for our Belay tops and tough enough for expedition use in our Omega clothing, while the Kappa clothing makes full use of both its qualities. HS2 is completely waterproof (when the seams are taped) and offers excellent breathability. (Weight: 88gsm).

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