Sleep systems

UK Camp – 3 Season: System 1

Carry a real minimalist bag, but sleep warm by linking it to the superlight Wafer clothing. The Wafers will keep you warm around camp, then boost your bag's performance at night.
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.
3°C / 37.4°F
Schematic representation of Sleep System. Actual components differ.


  • System Products:
    • Main Sleeping Bag: Minim Ultra K (Sleep Rating: +8°C / 46.4°F)
    • Plus Items:
      • Wafer Down Jacket
      • Wafer Down Trousers
      • Wafer Down Socks
  • ​​Full System Sleep Rating: +3°C (37.4°F)
  • Sleeping Bag Weights:
    • Minim Ultra K Sleeping Bag: 330g (11.6oz)
    • Standard lightweight Sleeping Bag to achieve Full System Warmth: 500g (17.6oz)


This system is designed for UK summer camping. The Ultra is a great summer bag down to night-time temperatures around 8°C. But we all know that we take a risk when we include May, June and September as ‘summer’ months. This System takes care of those cooler nights by adding the Wafer gear to provide a welcome boost in performance to +3°C.

Review relates to Minim Ultra K Sleeping Bag

"This is the smallest-packing, quality down sleeping bag I've seen. It fits into a jacket pocket. I've been as warm in this as I have been in bags twice the weight."
Trail Magazine.

Review relates to Wafer Down Jacket

"Amazingly light … packs down into a tiny ball. It's very comfortable to wear. I took the Wafer on the Scottish Watershed and loved it on chilly nights."
TGO Magazine's Gear Editor, Chris Townsend. Read Chris' full review.

Review relates to Wafer Down Trousers

"I wore my wafer trousers for three days non stop … never climbed in such horrific weather and conditions."
Jon Griffith climbing Link Sar, Pakistan.

Sleep system components

Works well with
From £504.00 330g +8℃
Warmth to weight at the limit of possibilities with the upgraded 'K Series' edition of this mountain marathon runners' and extra-keen backpackers' favourite.
From £457.00 190g 0℃
One of the lightest insulated jackets. A combination of an exceptionally lightweight fabric with PHD's unique 1000 fillpower down. A 'K Series' product: warmth to weight at the limit of possibilities.
From £403.00 130g 0℃
Our lightest insulated trousers. A combination of our lightest fabric with PHD's unique 1000 fillpower down. In stock: ships in 5 days.
From £199.00 45g
Boosts the performance of your ultralight sleeping bag. Warm feet from the tiniest package. Ships within 5 working days.