Sleep systems

Alps Winter: System 1

This system is based on the Hispar 500 sleeping bag, which gives superb warmth to weight performance, a -15°C rating for less than a kilo. The down clothing will boost that all the way to -30°C when worn inside the bag. So no worries about the weather turning cold – you’ll still sleep warm. For climbing, the Yukon jacket has proved itself in the Alps, the Arctic, and even the Himalayas, as a lightweight with serious performance. Along with the Rondoy trousers it will cope with a bivvy down to about -7°C.
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.
-30°C / -22°F
Schematic representation of Sleep System. Actual components differ.


  • System Products:
    • Main Sleeping Bag: Hispar 500 (Sleep Rating: -15°C / 5°F)
    • Plus Items:
      • Yukon Down Jacket
      • Rondoy Down Trousers
      • Minimus Down Socks
  • Full System Sleep Rating: -30°C (-22°F)
  • Sleeping Bag Weights:
    • Hispar 500 Down Sleeping Bag: 915g (32.3oz)
    • Standard lightweight Sleeping Bag to achieve Full System warmth: 1310g (46.2oz)


The Hispar 500 bag by itself is rated at -15°C, warm enough for valley camps through most of an Alpine winter. When the temperature drops even further, wearing the down clothing inside the bag will boost the performance rating enough to cope with a bitter -30°C. 

On the mountain the Yukon jacket is rated to -15°C and combined with the Rondoy trousers will cope with a bivvy at about -7°C. Needless to say, winter camping will also be a more pleasurable experience wearing this down gear.

K Series: The Hispar 500K Sleeping Bag is available in the K Series: performance is the same, but the exceptional loft of 1000 down reduces the weight of the bag to an amazing 770g (27.1oz).

Review relates to Hispar 500 Down Sleeping Bag

"The lightest bag tested yet warmer than some ... The Hispar 500 really does deserve the description 'Ultralight' ... The loft really is astonishing for such a lightweight bag ... the Hispar 500 is my favourite of the bags tested."
Chris Townsend, Winter Down Sleeping Bags test, TGO Magazine.

Review relates to Yukon Down Jacket

"Many thanks for the jacket that you supplied me for the Yukon Arctic Ultra. [It] performed perfectly in temperatures down to -35°C. The light weight and small size was also a huge help and helped me gain second place in the race. I ... am now the second fastest person over the course and the fastest European."
Dr Stuart Gillet (wearing a prototype Yukon jacket).

Review relates to Rondoy Down Trousers

"The lightest 'big mountain' down legwear that PHD has produced. They use 950 fill down, water-resistant Ultrashell face material and have full-length side-zips for ease of use. Serious cold weather trousers."
OutdoorsMagic Review.

Review relates to Minimus Down Socks

"The Minimus trousers and socks are amazing. The combination of weight, compressed volume and insulation properties is outstanding. With down I was able to reduce my pack weight significantly."

Sleep system components

Works well with
From $1,052.12 915g -15℃
Mountain lightweight for cold conditions. Ideal for fast ascents and quick travel.
From $743.34 400g -20℃
Our lightest big mountain and high-altitude trekking down-filled trousers. Now also available in custom sizes.
From $221.10 90g
Unbelievably light down-filled sock for warm feet in cold tents.