Alpine Ultra Half Bag

Our Alpine half bag (pied d'elephant) to insulate legs and feet. Camp down to 3°C and bivvy down to -10°C (with a suitably warm jacket)
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
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.
250g / 9oz
Alpine Ultra Half Bag

The Alpine ultra half bag has been excellent. I'm a great fan of the anorak/half bag combination and have used it for many years.
Mick Roffe



  • Outer fabric: water-resistant Ultrashell. An excellent balance of weight, water-resistance and breathability
  • Inner fabric – Ultralight MX
  • Rare 950 fill-power European Goose down
  • Stitch through construction to prevent down shift
  • Oval foot-piece for comfort
  • Reflective strip for night location
  • Stretch draw-cord with cord lock
  • Stuff sac – 10 x 18cm*

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


Camp down to 3°C and bivvy down to -10°C or lower.*

The mate for the Alpine Ultra jacket. The jacket is a superb stand-alone, but twinning it with this half-bag widens its capabilities. Camp down to 3°C and bivvy down to -10°C or lower.*

Half-bags are back

Half-bags (Pied d'elephant to oldies) are coming back. They've been out of fashion for many years in the trend towards using lifts and huts to make quick comfortable ascents, when a bivouac was a mistake, not a plan.

But the logic behind half-bags is still valid. If you're wearing a warm jacket already, all you need to spend the night out is something to keep your legs warm and there's no lighter way to do that than to use a half-bag. Check out the weights of PHD's half-bags and see for yourself.

  • When there's no hut in the right place for your climb, or it's full, or you just don't like the crush
  • When you want to wander along your GR, free to sleep inside or under the stars as the fancy takes you
  • When you want a lightweight backup in case weather, miscalculation or accident catch you out

...A half-bag is the lightest answer.

*Note on Temperature Ratings

We have given two separate TOTs (Typical Operating Temperatures) for this half-bag.

  • 'Camp' is for the times people might want to use it for lightweight camping instead of taking a sleeping bag (an appropriate jacket and ground insulation is assumed): this is a standard TOT, meaning you should be able to get a good night's sleep under normal circumstances.
  • 'Bivvy' gives a range of temperatures from the usual doze level down to the point beyond which you're liable to be awake and getting cold. Again an insulated jacket is needed.

All these figures assume you are wearing normal clothing inside the half-bag. Any insulated kit like down trousers and down socks will improve the TOT.

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.

950 fillpower down

A newcomer to our range. European goose of rare quality. A high value alternative at the top levels of performance. More on our down insulation.

"The Alpine ultra half bag has been excellent. I'm a great fan of the anorak/half bag combination and have used it for many years – warm enough most of the time in this country (UK). The system is ideal if you tend to fidget about in the night and find sleeping bag entry + zips + keeping tabs on the dog all a faff particularly when it’s wet and easy to get the inside of larger sleeping bags damp."
Mick Roffe

"It's now my go-to sleeping bag for overnight adventures. The bag itself is extremely lightweight, almost to the point of feeling fragile, but has kept me warm 3000m up a mountain in the alps, and on numerous trips around the UK without sustaining any damage. I'd definitely recommend a decent half bag to anyone looking to cut down the weight and size of their sleeping kit. It'd be particularly useful for bikepackers, alpine mountaineers and trail runners!"
Jake Baggaley.

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