Minim Ultra Down Sleeping Bag: K Series

Warmth to weight at the limit of possibilities with the upgraded 'K Series' edition of this mountain marathon runners' and extra-keen backpackers' favourite.
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.
8°C / 46.4°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.
330g / 12oz
Ultra Down Sleeping Bag: K Series

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.



  • PHD 'K Series': Ultimate warmth/weight performance
  • Unique PHD 1000 fillpower Down
  • Superlight MX outer fabric
  • Inner: Superlight 10X fabric. Down-proof, wind proof and super soft
  • Construction: Box-wall for max loft
  • Hood draws up close around head
  • Pack Size*: 13cm x 21cm
  • As used by Ed Stafford
  • Footpiece: Ovoid shape to fit naturally to feet and avoid pressure; multibox section covers whole foot area
  • Straight-wall baffles for lightness
  • Stuff-sac and mesh storage bag supplied
  • Colour: Black
  • Set options:
    • Ultrashell water-resistant outer. An excellent balance of weight, water-resistance and breathability
    • Waterproof Dri-LX outer fabric shell (+220g)‡
    • Short zip (left or right)
    • Full zip (left or right)
    • Slim, Wide and Extra Wide widths†
    • Short, Long, and Extra Long lengths†
    • Further customisation available via our Design Your Own Sleeping Bag service


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

‡Please note: The optional waterproof Dri-LX outer provides an extra seam-sealed outer shell to the bag. While a shelled sleeping bag is not designed to be used alone in heavy rain (the hood area is open to the elements) the shell does protect the bag when it is used outdoors without a tent.

†Please note: For all length and width options we change the amount of downfill to keep the warmth (TOT) the same.


This K Series product has been created for one single reason, to take warmth-for-weight performance to the limit of what's possible. Unique 1000 down, super-light materials, and specific design features mean that the word Ultralight now applies to this wide range of gear that will take you to the Poles as well as on a Sahara Marathon. More on the K Series...

To those who like to shave every gm of weight off their load, the Ultra K sleeping bag is designed for you. The 10X inner brings a new soft comfort as well as reduced weight, while the unique 1000 down ensures max warmth per gram. An ultralight dream at 330gm (11.5oz).

The optional waterproof Dri-LX outer provides an extra seam-sealed outer shell to the bag. While a shelled sleeping bag is not designed to be used alone in heavy rain (the hood area is open to the elements) the shell does protect the bag when it is used outdoors without a tent, for example in a snow-hole or under a tarp.

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.

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.

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.

Sleeping bag zips

  • No zip: The standard design on our lightest bags with open hoods. The simplest/lightest system which is a must for adventure racers. Up to 140gm (5oz) lighter than a full zip with draft tube.
  • Full zips: Full zip bags ventilate well, so they can be used over a wider range of temperatures.
  • Short zips: Short zips are lighter and pack smaller than full zips. A short zip & draft tube is up to 85gm (3oz) lighter than the full version.
  • Our full briefing on sleeping bag zips.

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.


This bag has an insulating straight wall baffle system throughout (no straight-through stitching). Straight wall is the lightest of all baffle sytems. In cross section it looks like this:

More on sleeping bag construction.

Reviews relate to previous version of this bag, which was 15g heavier

"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.

"I would, without a doubt, use the PHD Minim Ultra again. Quite simply, I don't think there's a better bag on the market for warm weather stage racing."
Bryon Powell -- member of 1st American team to place in top 3 of the Marathon des Sables.

"The bag was great for Marathon des Sables and I was 8th overall and the best finish ever by an American (or English speaker from what I hear). Anyhow, I loved the bag and will recommend it."
Michael Wardian.

"Just to let you know that I finished the Marathon des Sables. As you know i bought your Minim Ultra down sleeping bag, which was for sure the lightest in the whole race !!! and also during the nights i never feel cold !!! IT IS THE BEST PRODUCT I COULD EVER BOUGHT !!!! One more time ! THANKS THANKS THANKS.... YOU ARE THE BEST !!!"
Miguel Vingardi.

"A quick note to say how impressive my Minim Ultra was in the Sahara on this year's Marathon des Sables. Quite simply the best piece of kit I've ever bought. Temperature with wind got below 5 Celsius and the bag handled it so well that I slept in the buff every-night! Many, many thanks."
Ben Buckle.

"I was very happy with the Minim Ultra K and would highly recommend it to anyone preparing for the Marathon des Sables. All in all, great sleeping bag... helped me through the race without the need for a liner."
Kate McCaffrey (2017 MdS Competitor).

"What a pleasure; perfect weight, texture, size, color. Really what I was looking for. Nothing more nothing less."
Dominique P.

"I have a Minim Ultra bag. With this very nice piece of gear my rucksack was only 7.5 kg during a Summer Mountain Leader Assessment 3-days expedition. My assessors (Plas Y Brenin) were very impressed."
Dmitri Nikolaev.

"Seriously, this is the lightest bag I have, it might even be the lightest down bag I've seen ... The down itself is very soft indeed, almost textureless ... This super fine down plus the light and flexible MX fabric used on both items make the pack size unfeasibly small. The stuff sack for the bag takes my hand and wrist and that's it."

"Just bought the Minim Ultra [bag], used it for standard camping on Jura at the weekend, and will be bivvying with it on Skye next week. Initial impressions are that I'm seriously impressed with the weight and pack size, and it feels remarkably warm, thick and snug considering the puny weight. Definitely one to consider if buying [an adventure] race bag, that's exactly the reason i got it!"
Dave Wilby on forum.

"I'm now in the Pyrenees, hiking between the Pic d'Anie and the Breche de Roland. Your bag is keeping me wonderfully warm - such excellent quality at less than 500g is the envy of all my hiking companions!"
Deb R.

"I recently ordered a Minim Ultra sleeping bag from you. I received it on Saturday. It really is incredibly light and warm."
Jim Burton.

Geoff Stone.

"Just wanted to say thank you for sending me my Minim Ultra sleeping bag so quickly. It saved me a huge amount of weight for this weekend's LAMM (nearly 300g over my current lightweight bag), and kept me toasty and warm for a great night's sleep. Result: we finished 21st in the D class - a massive improvement on last year's 75th place!"
Sue Rowlands.

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