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PHD Mountain Software Ultra Down Pullover Review

The ultimate down jacket for ultralight backpacking and lightweight cold weather pursuits.

Hightly Recommended

Overall Rating: Highly Recommended

If I were to list my specifications for the perfect ultralight down jacket, it would describe the PHD Ultra Down Pullover exactly – ultralight shell, high loft down, good loft and warmth, great fit, minimal features, and really light weight. The jacket’s front reach-through pocket (with a zippered security pocket within) is a bonus, which I find really handy in camp. My only reservation is the jacket’s only moderate water-resistance, which is not really a problem for me, since I usually wear a shell over my insulating layer in wet weather.

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by Will Rietveld |


PHD Mountain Software Ultra Down Pullover Review - 1
PHD Ultra Down Pullover worn in camp at 12,000 feet in the southern Colorado Rockies. It’s insulated with 900 fill-power down and weighs just 8 ounces (size medium).

PHD (Peter Hutchinson Designs) Mountain Software is a small company in Stalybridge UK that manufactures sleeping bags and garments “from the lightest in the world to the ultimate in extreme expedition protection.” Their garments are offered in standard or custom sizing, plus options for added fill or features at additional cost. All products are sewn in their small factory after the order is placed. This review covers their new Ultra Down Pullover, which is designed to provide maximum warmth with minimal weight. Is this the ultimate down jacket for ultralight backpacking and lightweight cold weather pursuits?


The PHD Ultra Down Pullover features 900 fill-power down, which PHD tests on-site to be sure it meets or exceeds their specifications. One ounce of down of this quality expands to 900 cubic inches, so a relatively small weight of down produces a very puffy jacket. The jacket has sewn-through construction and 3.5-inch down chambers. I measured the jacket’s double-layer loft at 2.5 inches (single-layer: 1.25 inches), which is exceptional for a jacket that weighs just 8 ounces.

PHD Mountain Software Ultra Down Pullover Review - 2
Front and rear views of the PHD Ultra Down Pullover. Features include a half-length front zipper, stand up insulated collar, reach-through front pocket with zippered security pocket inside, dropped tail, and elastic hem and cuffs.

The loftiest down available is enclosed in PHD’s MX superfine nylon ripstop, which at 0.88 oz/yd2 (30 g/m2) is one of the lightest shell fabrics currently available. MX is calendared on both sides (more on the inside) to increase strength, wind resistance, and downproofness. The fabric weight is equivalent to that used in the Western Mountaineering Flash and Flight Jackets and slightly heavier than MontBell’s 7 denier Ballistic Airlight fabric 0.73 oz/yd2 (25 g/m2) used in their Ex Light Down Jacket. The latter fabrics are calendared as well. Calendaring increases fabric strength, wind-resistance, and downproofness, at the expense of some breathability.

As expected, the Ultra Down Pullover has a very Spartan feature set to keep weight to a minimum. The front YKK #3 coil zipper is twelve inches long. The cuffs have a simple elastic binding, and the hem has elastic at the sides rather than all the way around. Thankfully, the jacket has one front pocket, and it’s a good one - a full-width reach-through pocket with loads of room inside to hold an assortment of items.

PHD Mountain Software Ultra Down Pullover Review - 3
The front reach-through pocket (right) is full width and high volume. There is a zippered security pocket (left) inside on the right side.


PHD Mountain Software Ultra Down Pullover Review - 4
Cooking breakfast on a cold November morning in the southern Rockies.

I tested the PHD Ultra Down Pullover on a number of summer and fall backpacks in the southern Colorado Rockies and southern Utah desert over a five-month period. I also used it while backcountry skiing in late November. Nighttime temperatures ranged from 25-50 F (-4 to 10 C). I typically wore the jacket in camp and in my sleeping bag on colder nights.

I normally wear a men’s size large and found the sizing of the Ultra Down Pullover to be perfect. It’s roomy enough inside to wear over a baselayer plus a microfleece top, and the sleeves are extra long. The fit at the neck, wrists, and hem are snug, but not tight. The dropped tail covers the rear somewhat (see photos above) but the jacket is not extra long in the body.

One trip with this jacket is all it took to convince me that it is the ultimate down jacket for ultralight three-season backpacking in the mountains, winter backpacking in the desert, or cold (but not frigid) weather pursuits of any kind. For just 8 ounces of weight (9.1 ounces in size large tested), the Ultra Down Pullover has loads of loft and warmth. For hikers who prefer a hooded jacket, e.g., as part of their sleeping system, a hood is available as an option.

For cold weather camping, a dynamite combination is the PHD Ultra Down Pullover paired with a lightweight down pant - like the Western Mountaineering Flash Pant (7 oz), PHD Minimus Down Trouser (8 oz), or MontBell Down Inner Pant (6.8 oz). I am testing the mentioned pants for a future article, and find that the combination - scarcely adding up to one pound - not only provides plenty of comfort in camp but also extends the warmth of an ultralight sleeping bag by ten to fifteen degrees. I have found that wearing an ultralight rain jacket and pants over my insulating layers really increases their warmth in camp, and have been known to wear my raingear inside my sleeping bag on really cold nights to stay warm.

PHD’s MX fabric is super-light and is also quite durable and downproof. Worn alone, it’s very wind resistant, owing to the fabric being calendared inside and out.

PHD Mountain Software Ultra Down Pullover Review - 5
I tested the jacket’s waterproofness by placing a puddle of water on the shell for an hour (left), then checking for leakage. Water readily soaked through the seam, wetting the down, and creating a sizeable puddle on the inside of the jacket (right). The down in the area surrounding the puddle was completely wet and collapsed.

PHD Mountain Software Ultra Down Pullover Review - 6
I further tested the jacket’s water resistance by wearing it while hiking in a snowstorm at 31 F (0 C) (left). Water beaded up on the fabri, and eventually wetted the surface (right), but the water did not soak through the fabric and wet the down.

From my tests, I conclude that the jacket’s seams readily transmit water, but when the jacket is worn, it sheds water fairly well. The DWR treatment on the MX fabric is sufficient to repel a brief shower, but it is nothing exceptional - good, but not excellent. Compared to other jackets I have tested, e.g., the Rab Microlight Jacket which completely sheds water, the PHD Ultra Down Pullover has only moderate water resistance.

PHD Mountain Software Ultra Down Pullover Review - 7
The Ultra Down Pullover comes with a high quality, durable stuff sack that is properly sized for the jacket.


The following table compares specifications of jackets similar to the PHD Ultra Down Pullover. All jackets have ultralight shell fabric and premium down insulation. Manufacturer data for size medium are shown. All jackets have sewn-through construction except the Nunatak Skaha, which is baffled.

Jacket Shell Fabric Fill Power Measured Single Layer Loft (in) Features Weight (oz) size Medium Cost (US$)
PHD Ultra Down Pullover MX Microfiber
0.88 oz/yd2
900 1.3 Half zip, reach-through front pocket, zippered security pocket, elastic cuffs and hem 8.0 ~284
MontBell Ex Light Ballistic Airlight
0.73 oz/yd2
900 1.0 Full zip, elastic cuffs and hem 5.7 165
Nunatak Skaha Pullover Pertex Quantum
0.8 oz/yd2
850+ 2.0 Half zip, baffled construction, drawcord hem, elastic cuffs 9.0 319
Western Mountaineering Flash Dot-Ripstop Nylon
0.9 oz/yd2
850+ 0.9 Full zip, hood, two side pockets, elastic cuffs and hem 9.0 260
Western Mountaineering Flight Dot-Ripstop Nylon
0.9 oz/yd2
850+ 1.9 Full zip, two side pockets, drawcord hem, elastic cuffs 10.5 250

There are numerous high quality ultralight down jackets to choose from. The closest competitor to the PHD Ultra Down Pullover is the Nunatak Skaha Pullover, which is baffled and has more loft. Because of the low current (late 2009) valuation of the US dollar versus the British pound, the Ultra Down Pullover is a bit pricey, and the Nunatak Skaha Pullover is perhaps a better value (about 60US$ more. Also note that buyers outside the UK do not pay VAT, so 15% is deducted from the price when purchased). However, when the dollar is strong, the Ultra Down Pullover is an excellent value.


Based on its fit and exceptional loft and warmth for its weight, the PHD Ultra Down Pullover is my new favorite jacket. This is the jacket I will pack when I’m expecting nighttime temperatures to drop down to freezing or lower. It’s rated at 23 F (-5 C), and I would say that’s a fair rating. For spring and fall backpacking in the mountains, the Ultra Down Pullover gives me the extra warmth I need. I would also use it for summertime backpacking when I expect to camp above 12,000 feet. A jacket like this will also perform well for many wintertime activities, like backcountry skiing and snowshoeing, but would be too warm for extended climbs, unless it is really cold and/or windy. Finally, I prefer to wear the Ultra Down Pullover as a midlayer with a light shell over it to keep it dry and protect it from branch stubs and other things that might puncture it.

For an ultralight jacket, the Ultra Down Pullover is at the warm end of the scale, equivalent to the warmth of many jackets that weigh 14 ounces or more, but not as warm as the Nunatak Skaha and Western Mountaineering Flight. Some hikers may want to extend this jacket’s warmth a little more by ordering it with overfill and a hood so they can use it for winter camping. And some hikers may need less warmth, so a thinner jacket like the Montbell Ex Light Down Jacket or Western Mountaineering Flash may suffice. Of course, there is always the option of owning more than one jacket so you can match your insulation to the expected conditions.

Specifications and Features


PHD Mountain Software (


2009 Ultra Down Pullover


Half zip pullover


Outer shell and lining are 0.88 oz/yd2 (30 g/m2) MX Microfiber mini-ripstop nylon, calendared both sides, DWR finish


900 fill-power down


Measured two-layer loft is 2.5 in (6 cm)


Sewn through construction with 3.5-in (9-cm) horizontal quilting, down filled stand up collar, half length front #3 YKK coil zipper with one slider and storm flap under zipper, reach through front pocket with zippered security pocket inside, elastic cuffs and hem, 2-inch (5-cm) dropped tail, stuff sack included


Measured weight, size large tested: 9.1 oz (258 g)
Manufacturer specified average weight: 8 oz (227 g)


£169 (approx. US$284) Price includes VAT; if the item is to be delivered outside the EU, VAT does not apply, and 15% is deducted from the price
Disclosure: The manufacturer provided this product to the author and/or Backpacking Light at no charge, and it is owned by the author/BPL. The author/Backpacking Light has no obligation to review this product to the manufacturer under the terms of this agreement.


"PHD Mountain Software Ultra Down Pullover Review," by Will Rietveld. (ISSN 1537-0364)., 2010-01-26 00:05:00-07.


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PHD Mountain Software Ultra Down Pullover Review
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Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
PHD Ultra fill amount on 01/27/2010 15:39:58 MST Print View


I reverse engineered a Minimus per Lynn's explanation. I then used this information to determine the base layers clo and MET level that corresponded to the Minimus temperature rating. From the preceding I used PHD's temperature rating of the Ultra to determine its fill amount.

Diplomatic Mike

Locale: Under a bush in Scotland
Re : Fill power on 01/27/2010 15:49:36 MST Print View

Cheers Richard. I was hoping you had uncovered a PHD secret file of fill weights. :)

Will Rietveld
(WilliWabbit) - MLife

Locale: Southwest Colorado
Responses to PHD Ultra Pullover Comments on 01/30/2010 18:48:57 MST Print View

Hi all. My responses:

Franco: Yes, that is a BSI Mirage 1P. I will be publishing a review on it in the spring.

Mike/Lynn: PHD doesn't like to reveal the amount of down in their garments, citing the problems all manufacturers have with others copying their designs.


Franco Darioli
(Franco) - M

Locale: @Tarptent
PHD Mountain Software Ultra Down Pullover Review on 02/02/2010 16:37:50 MST Print View

Thanks Will. Looking forward to it.

jim jessop
(LuckyJim) - F
PHD Ultra Down Pullover clo value? on 03/09/2010 13:52:16 MST Print View

Hi all and especially Richard if you pass by.

I've seen your extrapolation of estimated down weight for the PHD Ultra but I'm not able to find a clo value for it. I wondered if that is something you've measured or commented on anywhere?

Many thanks

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: PHD Ultra Down Pullover clo value? on 03/09/2010 15:10:21 MST Print View


The Iclo value for this garment is 2.74. The closest equivalent warmth Montbell garment is the MB Light Down Parka at 2.80.

Phd rates this garment at 23F (-5C). My calculations yield 21F for the average male, 1 clo of base layers, sheltered from the wind, and a 2 MET camp chores metabolic rate (standing rather than the typical MET rating scenario based on sitting). PHD assumes either the addition of a sweater to the average winter base layer or a .25 MET higher metabolic rate than is the average for camp chores. At the more typical 1.75 MET activity rating this is a 30F garment.

Edited by richard295 on 03/09/2010 15:11:23 MST.