K Series Omega Down Suit

The superlight 'K-series' version of our Omega Suit. Developed for a winter ascent of K2 and warm enough for periods of inactivity in the extreme cold. Lighter and warmer than our standard Omega Suit for winter ascents of the 8000m peaks.

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.
-60°C / -76°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.
1875g / 66oz
K Series Omega Down Suit

As used by Mingma David Sherpa on the first winter ascent of K2, 16 January 2021.



  • A PHD 'K Series' Product: Ultimate warmth / weight performance
  • Unique 1000 fillpower European Goose down
  • Lightweight waterproof Dri-LX outer fabric shell with fully-taped seams
  • Superlight 10X inner. Down-proof, windproof, and super soft
  • Box-wall construction for maximum loft. Differential Cut allowing full down loft.
  • Front closure: 2 way zip covered by double baffle and Velcro
  • Short side zips - ankle to knee
  • 9 pockets:
    • 2 cargo pockets
    • 2 handwarmer pockets
    • 1 storage pocket under front flap
    • 4 inner water-bottle pockets (for 500ml Nalgenes) with elasticated entry
  • Hood:
    • large size with rear volume reducer
    • elastic face cord with cord ends channels
    • peak
    • sewn on with adjustable front Velcro closure
  • Knees and elbows articulated through all layers
  • Rainbow seat zip for toilet access
  • Ankle reinforcement patches
  • Elasticated waist and elasticated inner back for snug fit
  • Warm Knitted cuffs
  • Internal braces - adjustable for varied clothing - removable
  • Reflector tape on pockets and back of hood for night searches
  • Beard flap
  • Mitt attachments at chest
  • Stuff sac
  • Pack size: 25 x 44cm* 
  • Options:
    • Colours: Red, Green, Black (in all colours the shoulders, knees and seat are black)
    • Pit zips (+£50)
    • Thigh-length side zips (+£50)
    • Hood attachment (zip-on/sewn-on)
    • Under and Up zip as alternative for toilet access.


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


As used by Mingma David Sherpa on the first winter ascent of K2, 16 January 2021.

This superlight ‘K-series’ version of our standard Omega Suit was developed for a winter ascent of K2. Its lighter weight and greater warmth make it suitable for extremely cold and technical high-altitude expeditions. It is also suitable for lightweight polar expeditions.

A fully waterproof outer shell protects the down on long and arduous expeditions in truly inhospitable conditions.

The huge depth of down insulation and a differential cut—designed to allow full lofting—delivers an immensely high-performing suit. The warmth provided by the Omega Suit has proved a life saver in extreme conditions.

The Omega ‘K’ suit has full expedition specifications, with box-wall construction, expedition-style pockets inside and out, a voluminous hood and many other features.

This ‘K-series’ version is 425g lighter than our standard Omega suit due to a combination of our unique 1000 fill power down and the use of our new, lightest-ever, 2-layer breathable waterproof rip-stop fabric, Dri-LX, which weighs just 64gsm.


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 body width, body length, inside leg and arm length 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.


Toilet access on suits

  • Under & Up zip: The central front zip on the suit runs from the collar, down the front of the body, past the groin and then under and up to waist level at the back. A two-way zip allows access at any place.
  • Rainbow Seat zip: A rainbow / semicircle zip is sewn in across the backside. A two-way zip allows access and creates a drop down flap.
More on toilet access.

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.

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.

Reviews are for our standard Omega Down Suit, which is 425g heavier and 5℃ less warm

"The Omega down suit was wonderful on my successful summit of Makalu. We reckon it was down to minus 45 degree C on summit day and I was toastie. I cannot thank PHD enough as the suit made all the difference and certainly contributed to my summit success."
Adele Pennington.

"I went to Everest as leader of Jagged Globes' North Ridge Expedition; this expedition included Sir Ranulph Fiennes who I believe you also supplied with down gear. The expedition was successful in placing six out of nine clients on the top ... [The] down suit [you made] to wear on Everest ... worked perfectly and will be using [it] again."
Neal Short.

"Very well made items of clothing with tons of features ... perfect for kiting on the Antarctic plateau where temperatures will be regularly lower than -35C."
Team N2i.

"Summit day was clear and relatively warm, but five days earlier [our] party was forced back at 8500m during the middle of the night in the teeth of a fierce wind storm. This is where the [PHD down suit] really proved its worth, just as it had on a previous attempt when [I] turned back between Camps 3 and 4."
Paul Deegan, author 'Mountain Traveller's Handbook', on his Everest ascent.

"The light down fill [version] is perfect for the Australian Alps region. I've sat outside in a raging snow blizzard and felt no discomfort whatsoever while the rest of my skiing party were huddled together in a storm tent around a heater! I loved the wear patches and reflective stripes! Thanks again guys, this is top notch gear!"

"I have just received the Omega suits, thanks. They're great, just [as] I expected. The new inside pockets are awesome."

"The Omega suit is fantastic and a perfect fit."
'Lanx', Equipment buyer, UK Reserve Forces Seven Summits team.

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