Sleep systems

High-Level Treks: System 2

This versatile system is based on the superb Hispar 400 sleeping bag. The lightweight Minimus clothing will keep you comfortable through the day and can then join the Filler bag at night in giving the Hispar 400 a boost all the way to -29°C. A good margin even if the weather turns cold.
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.
-29°C / -20.2°F
Schematic representation of Sleep System. Actual components differ.
“This has to be the best sleeping bag I've ever used in every respect.”


  • System Products:
    • Main Sleeping Bag: Hispar 400 (Sleep Rating: -9°C / 15.8°F) Weight 790g/28oz.
    • Plus Items:
      • Minimus Down Jacket
      • Minimus Down Trousers
      • Minimus Down Socks
      • Filler Down Sleeping Bag
  • Full System Sleep Rating: -29°C (-20.2°F)


Minus 10°C is about the coldest you would expect on most high-level treks (e.g. Everest Base camp), but nights are capable of dipping to -15°C or even below occasionally. This versatile system lets you choose the sleeping gear to suit the conditions. For the lowest temperatures slip the Filler bag inside the Hispar and wear the Minimus clothing to bed: this combination will give you a warm night down below -25°C. If it's more like -10°C to -15°C, you should find it enough to use either the Filler or the Minimus clothing to boost the Hispar 400. And whatever you opt to sleep in, you’ll be glad of the down gear on the trek and around camp.

The Filler bag does offer an advantage of its own. If parts of the trek are in warmer areas, the Filler is rated to +15°C as a stand-alone bag and would probably remain comfortable at close to +20°C, offering an option for warmer nights (or teahouses).

K SeriesThe Hispar 400K 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 655g (23oz).

This review relates to Hispar 400 Down Sleeping Bag

"This has to be the best sleeping bag I've ever used in every respect. It weighs 790g and its warm as a very warm thing (good to -9). It's not cheap but then you get what you pay for when it comes to sleeping bags. PHD are a very small company but they beat the socks off the big guys."
Phil Newby, registered BAIML International Mountain Leader.

This review relates to Minimus Down Jacket

TGO Magazine best buy

"This jacket is remarkable for its warmth, weight and comfort, especially given the add-on option of a hood: I had no choice but to make it Best Buy ... It felt significantly warmer than any other sub-400g jackets and with the optional stud-on, snug-fitting hood ... it'd be awesome. The weight is unbelievable, given that the test jacket features the heaviest, most water-resistant fabric option (Drishell) ... Minimus is amazing."
Judy Armstrong in TGO Magazine.

This review relates to Minimus Down Trousers

Backpacking Light - Highly recommended

"Overall Rating: Highly Recommended. These down pants are simple and light, just the way we want them. They have the most loft and highest loft:weight ratio of the three pants we tested; I couldn't ask for more. I found that I could extend the warmth of a 30°F (-1°C) sleeping bag to 15°F (-9°C) by wearing these pants and a lightweight down jacket inside."
Will Rietveld, Backpacking Light. Read full review.

This 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."

This review relates to Filler Down Sleeping Bag

"It is a pleasure, when you know the temperature is dropping, just to slip into another bag and double the warmth factor."
Sam Cook.

Sleep system components

Works well with
From £781.00 790g -9℃
Mountain lightweight for cool conditions. Ideal for fast ascents and quick travel.
From £560.00 280g -5℃
Our lightest and best ever Minimus down jacket: just as warm as ever, but more fully-featured and now even lighter. Now also available in custom sizes. Favoured by trekkers, runners and mountaineers all over the world.
From £174.00 90g
Unbelievably light down-filled sock for warm feet in cold tents. 
From £486.00 240g +15℃
A lightweight liner that boosts your sleeping bag's warmth by 10°C. On its own, the lightest of sleeping bags. A PHD 'K Series' product: warmth to weight at the limit of possibilities.