WaferLite Down Jacket: 'K Series'

The lightest down jacket in the world, made with our 7-denier fabric (7X) and 1000 fill-power down. Now also available in custom sizes.
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.
5°C / 41°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.
130g / 5oz
WaferLite Down Jacket: 'K Series'

If any item astonished me this year it was this jacket. There's no reason to ever leave it behind.
Chris Townsend, Equipment Editor of The Great Outdoors (TGO) magazine



  • A PHD 'K Series' product: Ultimate warmth/weight performance
  • Unique 1000 fillpower European goose down
  • Inner and outer: sheer-light 7X fabric, our lightest ever
  • Stitch through construction for maximum weight saving
  • Down filled collar to seal in the warmth
  • Full-length front zip
  • Elasticated hem
  • Lycra cuffs
  • Drop-tail hem
  • Stuff sac supplied, 10 X 18cm*


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


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, choose your body width, and then the body/arm lengths, shorter or longer, 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.

At 130grams the WaferLite jacket is the lightest down jacket in the world

The combination of windproof 7X fabric (our lightest) and our unique 1000 down results in a wonderfully flexible layering piece with the highest warmth-for-weight performance possible from down. Packed into a tiny stuff sac, the K Series WaferLite jacket is simply breathtaking.

It’s less than a third the weight of a mid-weight fleece and warmer too (and don’t forget it's totally windproof).

This is not high-mountain gear, nor is it ideal for doing dirty car repairs (fleece has its uses). But for the pure gift of warmth from something you could literally stuff in your pocket it has no rivals.

The features list is short: it’s what’s not featured (such as pockets) that makes the Waferlite such an individual piece -- and ultimately the lightest possible down-filled jacket.

  • Use to give a temperature boost to your sleep system
  • Pack without noticing the weight or bulk
  • Outer layer or mid-layer warmth
  • Warmer, lighter, and smaller pack-size than a fleece jacket and 100% windblock too

The WaferLite range are summer-camping super-lights that give real warmth around camp and can boost your sleep system. This WaferLite Jacket or the WaferLite Vest combined with the Wafer Trousers and socks provide a comfortable sleep suit for use with sleeping bags and quilts.

Ultralight 7X fabric (weight: 22 gsm)

7X is our new sheer-light 7 denier fabric. An exquisitely fine rip-stop nylon, 7X is incredibly light, highly wind-resistant and has first-rate down proofing. This fabric helps us create the very lightest of gear in the PHD range. Of course the lighter the fabric the lighter the sleeping bag or down clothing, and the less space it takes up in your rucksack. This fabric is so light it actually helps to allow even greater lofting of the down too.

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.

"If any item astonished me this year it was this jacket. It weighs 131 grams - less than many base layers - yet is filled with down and as warm as a heavyweight fleece. To keep the weight down there are minimal features - no hood, no pockets - and an ultralight shell. The down is 1000+ fill power, which is as high as you can get. At this weight and tiny pack size (about that of a grapefruit) there's no reason to ever leave the Waferlite behind."
—Chris Townsend, Equipment Editor of The Great Outdoors (TGO) magazine


"I wanted to carry less weight but enough warmth for the Marathon des Sables. My ambitions were performance, so minimum weight was very important. I finished 24th. I put the Waferlite Jacket on every evening and on some nights inside my PHD Desert One Sleeping bag. The jacket was light, packable, and warm. Great stuff!."
—Sam Gully