Expedition Double Suit (-35C)

An expedition double suit made of 2 layers: a one-piece Inner Down Suit & a two-piece Outer (down Jacket & Trousers). Designed to cope with the extreme temp. range in high altitude mountaineering.
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.
-35°C / -31°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.
1300g / 46oz
Composite image showing cut-away of Inner (right) & Outer (left).
Your double suit is the most versatile out there. When Ben Fogel wore his when we both summited Everest he was able to regulate his heat way better than I could in a more traditional suit.
Sixteen times Everest summiteer and expedition guide, Kenton Cool


Inner Suit

Weight: 550g (19oz)
Typical Operating Temperature: Inner alone: -10°C (14°F)


  • Ultra-light one-piece inner suit
  • Colour: White, to reduce solar gain 
  • Lightweight M1 inner and outer fabric
  • Rare 950 fillpower European pure goose down
  • Front closure: Two way zip with under baffle
  • Beard guard
  • Elasticated waist for close fit
  • Pit zips for maximum venting
  • Hand warmer heat-pad pockets inside the sleeve
  • Lycra cuffs
  • Toilet access: Rainbow zip. Alternative option - Under and Up
  • Four pockets:
    • Two outer cargo pockets (insulated for camera etc) 
    • Two inside twin water-bottle pockets with elasticated entry (to hold 4 x 500ml Nalgene bottles)
  • Hood:
    • Zip on with adjustable front velcro closure
    • Lycra edged for simplicity
    • Rear volume reducer
  • Reflect tape on the pockets and back for night location
  • Zip pulls for easy operation in mitts
  • Stuff Sac
  • Pack Size: 17 x 28cm
  • Options:
    • 'Under and Up' zip as alternative Toilet access
    • Zip-on or sewn-on hood
    • Leg zips for venting:
      • Thigh-length (+£50). Adds 50g
      • Full length (+£65). Adds 100g

Outer 2-piece Suit

Weight: Jacket 450g (16oz). Trousers 300g (11oz)

Common Features:

  • Ultralight two-piece outer suit (jacket and trousers) 
  • Sized to allow full loft of the inner suit
  • Allows access to climber's harness
  • Clip loops for lanyards (e.g. Jumars)
  • Water-resistant Ultrashell outer fabric
  • MX inner fabric
  • Rare 950 European Pure Goose Down
  • Stitch-through construction for lightness
  • Blue Ultrashell outer fabric
  • Option:
    • Green Dri-LX outer fabric for extra durability (+£50) Adds 120g


  • Front closure: Two-way zip with flared over-baffle (to protect the water drips from an oxygen-mask freezing and locking the zip)
  • Lanyard clip loops
  • Four pockets
    • 2 Large outer cargo pockets (insulated)
    • 1 through pocket to access the inner suit pockets
    • 1 Large inner security pocket 
  • Hood:
    • Zip-on with adjustable front velcro closure
    • Elastic cord adjustment around the face
    • Rear volume reducer
  • Pit zips for maximum venting
  • Adjustable cuffs
  • Fleece-lined collar
  • Adjustable waist cord and elasticated inner back for snug fit
  • Beard flap
  • Shock Cord Hem
  • Zip pulls for easy operation in mitts
  • Stuff sac
  • Pack size 17 x 28cm
  • Options:
    • Zip-on or sewn-on hood
    • Oxygen mask extender (+£30)


  • Tie-in slot for access to climber's harness
  • Full-length, two-way, side zips with underbaffle for increased insulation
  • Toilet access: drop down seat
  • Lightweight braces - removable
  • Articulated knees
  • Fly zip
  • Adjustable waist cord
  • Stuff sac
  • Pack size: 17 x 28cm


Designed to function in extreme cold and at very low oxygen levels, down-filled suits have become standard for high-altitude mountaineering.

However, over the course of a long day, mountaineers can face enormous temperature changes from factors—such as wind speed and cloud cover—completely beyond their control.

Heat-exhaustion and fatigue from dehydration often cause more of a problem than the cold, and a climber’s harness can make things worse, preventing the removal of a single suit.

The PHD Expedition Double Suit solves these very real issues. It is a more versatile and much lighter system than single suits, with more comfort and ease of movement.

The Inner suit can be ‘lived in’ from the lower camps to the summit, while the 2-piece Outer suit is easy to put on for the summit push or whenever conditions require it.

Innovative features like heat-pad pockets at the wrists, a harness tie-in slot, lanyard clip loops and the flared storm baffle all add greater functionality and performance to the system. Dri-LX outer fabric is an option for trips where extra durability is the most important factor.

The first of its kind in the world, the PHD Expedition Double Suit is a whole new approach to down clothing for high-altitude mountaineering.

Two versions of this suit are available:

  • This Standard with a typical operating temperature of: -35°C (-31°F)
  • A Warmer version with a typical operating temperature of: -50°C (-58°F) and recommended for no-oxygen ascents on 8000m peaks
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.

The Starting Point

Our founder, Peter Hutchinson, made the first ever one-piece Down Suit (for Don Whillans on Everest) in 1971. Since then the design has been recognised as the best kit for the highest peaks and copied world-wide. Improvements have been made, but there has been no radical change until the new PHD Double Suit in 2017.


The sparks that set us thinking about the new Double Suit go back some way. Feedback from Himalayan expeditions ever since the 1990’s raised a number of points which allowed us to improve our high altitude gear. Two questions kept coming back:

  • Could we cut down the weight and bulk of our extreme sleeping bags?
  • Down suits gave excellent protection, but they were often too hot on the way up to the high camps: could we make them more wearable across a wide range of conditions?

We kept making our suits and sleeping bags lighter and lighter without fully answering either problem, until we decided it was time to think things out from scratch. Only at that stage did we start to realise that these questions were linked. 

Sleeping Light: The Easy Bit

Sleeping bags for the high Himalayas have to cope with extreme cold. That’s a definite. But keeping down clothing on at night inside the bag means a much lighter bag can deliver all the warmth needed. It had often been done on an ad hoc basis, so we simply designed the best combinations to work in the most effective way and made it possible to plan expedition night gear in a new way.

After tests at altitude, that came out as our award-winning Sleep Systems in 2016. First question answered.

Daytime: The Hard Bit

How could we make a suit warm enough for the summit that didn’t fry the user on the lower slopes?

A traditional Down Suit has great advantages in protection and simplicity, but once you’ve put it on, you’re in there for the day, maybe the week. The range of temperatures you pass through on a big mountain are enormous. No question you’ll need the suit on your summit push, but on the way up in places like the Western Cwm on Everest you may overheat beyond the point where any ventilation system can cope. 

Then we hit on the idea of splitting the traditional single down suit into two. One on top of the other, both extremely light. 

The one-piece inner suit for the climb up to 7000 metres where overheating seemed to be a common problem. The two-piece outer a quick overfit to bring the combined double suit up to full summit performance at 8000+ metres.

We had to solve a number of design difficulties and our first tests of the double suits on both sides of Everest were stopped short by the avalanches of 2015. Since then success on two separate 8000m peaks in 2016 confirmed that this really is the way to go. Surprisingly the double suit is lighter and simpler to use than a single and offers a whole new versatility of temperature control, both day and night.







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.

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.

Lightweight M1 fabric (weight: 39 gsm)

Lightweight silky microfibre. This close-weave 20 denier fabric is fully downproof, but also light and flexible enough to allow the down full loft. A reliable performer that has been the basis for much of our lightweight gear for some time.

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.

950 fillpower down

A newcomer to our range. European goose of rare quality. A high value alternative at the top levels of performance. More on our down insulation.

"Your double suit is the most versatile out there. When Ben Fogel wore his when we both summited Everest he was able to regulate his heat way better than I could in a more traditional suit."

Sixteen times Everest summiteer and expedition guide, Kenton Cool

"For a suit that is literally made to measure and is totally fit for purpose then look no further. You get exceptional value for money and it's more versatile than the other suits available. 9.25/10."

[Tim rated the PHD Double Expedition Suit 1st in his review of down suits by PHD, Rab, Mountain Hardwear, North Face, Berghaus, Marmot, and Mountain Equipment.]

Six times Everest summiteer and expedition guide, Tim Mosedale (read full review)

"The Double Suit is mega. It's a really great system. I can't climb when I get hot and the Double Suit is just perfect for avoiding over-heating. I hate faff and the idea of having to unzip a traditional down suit and have it hanging around your waist is the kind of thing that makes my blood boil. I watched climbers leaving Camp 2, often in the afternoon in the heat of the Himalayan sun, on their way to Camp 3 in full down suits and it looked terrible. I wouldn't have been able to take ten steps without steaming up and going back to camp!"

Jon Griffith using the PHD Expedition Double Suit on Everest

"The double suit performed extremely well again on Dhaulagiri this Autumn. When we climbed from Camp 1 (5700m) to Camp 2 (6650m), I was the only climber to be comfortable in the conditions all day. I climbed in the inner suit and base layer all day, only having to vent the pit zips from time to time. The others started in down suits and two-pieces, having to stop, remove harness and crampons etc, some climbing in down salopettes without jackets. It was another reaffirming moment that the design really does work. A faulty head torch on the summit push left me stranded without supplemental oxygen at 7600m from 2am to 5am waiting for the sun to come up. I'm not the warmest person and I managed to stay warm enough, which shows how effective the full combo suit is. Keep up the great work."

Ben Kane using the PHD Expedition Double Suit on Dhaulagiri

"I found a single base layer and the inner suit is about all I needed in temperatures above -10 Fahrenheit (-23C), as long as I was moving, and the wind was less than 15 knots. In colder temperatures I put the outer suit on. I only need to wear the inner suit on the way back to camp 3! I took off the outer trousers by the 3rd step. On the summit I had the outer jacket on, but open. Other climbers in traditional down suits were feeezing/dripping wet with sweat, especially when climbing the North Col! People were giving up from sweating too much."

Frank Campanaro using the Double Down Suit on Everest


"I came to love the suit. Most of the time prior to summit day I did not need the outer top, being warm enough with just the inner and the overtrousers. On summit day I wore the jacket as well. I think the design that allows the harness to be worn on the inner, with the yellow gear loops on the outer jacket, is terrific. By the end of the trip, I was positively flaunting the suit, I was so pleased with it. Great suit. I look forward to my next chance to use it."

James Strohfeldt using the Double Down Suit on Everest North Ridge

"Although, with wind-chill, the temperature was about minus 40°C, I didn’t feel cold at any time during my 17 hour summit push. Even in the notorious queue back down the Hillary Step, I did not once feel cold. I give credit to my PHD Double Down suit for this. On the descent to Camp 4 it was a Godsend to be able to remove the down jacket and be way more comfortable than the majority of other climbers on the mountain. In fact, the one-piece base down layer was so effective that I only had to wear the outer down layer on summit day. Thanks again for making great mountain gear."

Roland Thomas using the PHD Expedition Double Suit on Everest


"On the summit, I was ample warm with just the inner suit and came down MUCH MORE comfortable than anyone else. Overheating was a major factor for my teammates - so much so that one almost didn't get down due to a combination of fatigue and heat-exhaustion. I was chipper on the other hand.

The beauty of the inner suit system was its softness and flexibility which allowed me to move a lot more freely than in a more conventional, bulkier suit."

Rob Casserley using the PHD Expedition Double Suit on Cho Oyu (8,188m)

"I absolutely loved your double suit on Everest and I would recommend it to all my climbing friends especially as it can be made to fit smaller people."

Rowena Lewthwaite using the PHD Expedition Double Suit on Everest

"I absolutely love the double suit combo. I wore the under down suit a lot at Advanced Base Camp. I found it kept me warm and was really handy. I would then add the jacket and trousers higher up for more warmth. But, I could also just wear the outer jacket. The down suit is super light and soft and not heavy which is great for carrying less weight. I liked the design and the pockets and the colour. I was never at any point cold."

Kirsty Watson using the Double Down Suit on Everest

"What I find most impressive is adaptability of the system. The inner suit is a 'live in' piece of gear, ideally for use above 6500m, up to over 7500m, possibly higher. Once I put it on, I didn't need to take it off until the descent to Base Camp. What I really like is this allows you to wear the suit over base and mid-layers and leave shell layers at lower camps. On average this will save around 1kg of weight.

Traditional down suits have been worn only from the higher camps up to the summit. In warm conditions the climber is either uncomfortable or takes the suit off and carries it in on their back. This system allows you to utilise the insulation you are carrying lower down, climb through greater temperature ranges and generally be more comfortable and adaptable to changing weather.

Overall, the materials used are on the cutting edge of design for high altitude gear, the build quaility is exceptional and the design concept of a double suit is functional and practical.

Ben Kane using the PHD Expedition Double Suit on Manaslu (8,163m)

"The PHD double suit has really many assets. In addition to the perfect fit and the build quality, for me one of the key advantages is its adaptability to different conditions. This came in very handy for me on Ama Dablam. Descending from the summit to Camp 2 in the blazing sun with a traditional single down suit would have been a nightmare!"

— Alessandro Dazio

"My summit suit was the envy of our climbing group. The flexibility of having an inner suit that you could wear alone for temperature control combined with all the little details having been thought of by PHD, from inner bottle pockets to gear loops and hand warmer pockets in the sleeves, meant that I was extremely confident in my kit going for the summit push. My sleeping bags were also PHD and were both exceptional, as were my slippers and minimus down vest which made for a brilliant layering option up the hill."

David Brock who summited Everest in the PHD Exhibition Double Suit.

"The double down suit was a life saver in this expedition, the heat during the way down from the summit was intense and to be able to take part of the suit off probably saved me from severe dehydration! Highly recommend PHD"

Steve Davis who summited Everest in the PHD Exhibition Double Suit.

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