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Rab Microlight Jacket Review

Trim-fitting ultralight three-season down jacket with a great shell and basic feature set, but its numerous horizontal seams allow down fragments to leak out.

Overall Rating: Above Average

It's appropriate to give this jacket the name "Microlight" because its Pertex Microlight shell is its dominant feature. I like the jacket's highly wind and water resistant shell, trim fit, and feature set, and its down insulation seems to be "almost 800 fill" but they don't call it that. The downside of this jacket is that the numerous horizontal seams leak down, and the hand pockets lack a good elastic binding. From an ultralight backpacker's viewpoint, the Rab Microlight Jacket is a bit heavy for the warmth it provides. Jackets with a lighter shell fabric, like the Western Mountaineering Flash Jacket and Flight Jacket, have a much better warmth to weight ratio. However, the Microlight Jacket is spot on for mountaineers and lightweight backpackers who want more durability and exceptional water repellency.

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by Will Rietveld |

Rab Microlight Jacket Review - 1
The Rab Microlight Jacket has a Pertex Microlight shell, 750+ down fill and weighs 11 ounces (size Large). Rocky Mountain goats in the background, Rocky Mountain old goat in the foreground.


An ultralight three-season down insulated jacket with high loft down, very light shell fabric, a minimal feature set, and weight under 14 ounces is an essential part of an ultralight or lightweight backpacking kit for summertime backpacking in the mountains or shoulder season camping most anywhere. Down insulation provides the most warmth for its weight, so it's the insulation preferred by backpackers and mountaineers in all but very wet conditions. An array of jackets is available - differing in fabrics, features, and amount of down insulation - so there's a jacket to fit most hiker's needs and preferences. Look for a Backpacking Light State of the Market article on ultralight three-season down insulated jackets in Spring 2010 that will present the options and assist with the selection process.


The Rab Microlight Jacket, as the name implies, utilizes Pertex Microlight fabric for the shell. Microlight, like other Pertex fabrics, is made of microfine filament yarns with an extremely close weave, and they are calendared to make them windproof and downproof. The fabric's high density weave also enhances insulation by trapping more air inside. However, Microlight at 1.3 oz/yd2 is a bit heavier than Pertex Quantum at 0.9 oz/yd2. Microlight features DWR+, which is a unique durable water-repellent treatment which encapsulates each filament of the fabric with a hydrophobic polymer. This treatment gives excellent water shedding, and since it is not a continuous coating, breathability is not impaired. Another unique property of Pertex fabrics is their ability to disperse water. Where most nylon fabrics wick moisture directly through the weave, Pertex spreads it over a broad area by capillary action, so it evaporates more rapidly.

Rab Microlight Jacket Review - 2
Front and rear views of the Rab Microlight Jacket. Features include a full front zipper, stand up collar, two side pockets, and zippered chest pocket.

The Rab Microlight Jacket shares several design elements with its siblings, the Microlight Alpine Jacket (hooded), and Microlight Vest. All have sewn-through 1.5-inch horizontal quilting to hold the down in place, two hand pockets, one zippered chest pocket, and elastic piping on the cuffs and hem.

Rab Microlight Jacket Review - 3
The Microlight Jacket has two unzippered handwarmer pockets (left), and one large zippered chest pocket (right) that doubles as a stuff sack.

The down insulation in the Microlight Jacket is 750+. I asked Rab why they don't use 800 fill power down to keep up with the competition, and their response emphasized the "+" sign after the "750," meaning their down has a minimum of 750 fill power, and is closer to 800 on average. Rab prefers to use a very conservative rating rather than inflate it for marketing purposes (not that others do...) so they call it what it is at the very minimum. From a consumer point of view, it still begs the question: "Is it, or isn't it, comparable to '800 fill' used by other manufacturers?"


Rab Microlight Jacket Review - 4
Rab Microlight Jacket worn while backpacking on a cold fall day.

I tested the Rab Microlight Jacket on several summer and early fall backpacking trips in the southern Colorado mountains, where I camped at elevations up to 12,500 feet (3,810 m) and encountered snow, wind, rain, cold nights, and lots of beautiful scenery. I wore the Microlight Jacket as an outer layer on cold days, as a midlayer with a shell over it for extra warmth and wind protection, and in my 30 F (-1 C) sleeping bag to extend its warmth on below freezing nights.

The jacket has a trim fit, both in the body and sleeves, so it will only layer over a base layer and a thin sweater. Sleeves are set-in at the shoulders and are plenty long.

I really like the jacket's roomy hand pockets, which will hold a bunch of smaller items in camp and keep them handy. The side pockets are not zippered and the elastic band in the binding has minimal stretch, so items can fall out if the pockets are overloaded. I found the zippered chest pocket handy for holding my digital camera to keep it dry and secure.

Rab Microlight Jacket Review - 5
The jacket's Pertex Microlight shell is very wind resistant and functionally waterproof (see next photo).

Rab Microlight Jacket Review - 6
I tested the jacket's waterproofness by placing a puddle of water on the shell for an hour, then checking for leakage. Nothing came through! Water eventually soaks through the seams in many jackets, but the Pertex Microlight shell on this jacket didn't allow any water to soak through.

The Microlight Jacket is warm down to about freezing at a low activity level, and warm down to colder temperatures when worn as a midlayer while hiking or skiing. From past experience with a Pertex Microlight windshirt, I find the fabric not very breathable (because it's calendered), but breathability is less important in an insulated jacket shell. Overall, the Microlight Jacket is extremely versatile (as are all ultralight three-season down jackets) and it saw a lot of use. I wore it during the day as needed, every evening and morning in camp, and inside my sleeping bag.

Rab Microlight Jacket Review - 7
Although the Microlight Jacket's 1.5-inch horizontal quilting is stylish and holds the down in place, the numerous seams also provide an easy route for down to escape. This microfleece top is covered with down fragments after wearing it under the Microlight Jacket in a sleeping bag overnight.

Comparisons and Assessment

Two jackets closest to the Rab Microlight are the Patagonia Down Sweater and Mountain Hardwear Nitrous Jacket. The following table compares their specifications; manufacturer data for size medium are shown.

Jacket Shell Fabric Insulation Features Weight (oz) Cost (US$)
Rab Microlight Pertex Microlight (nylon) 750+ down 2 unzippered hand pockets, zippered chest pocket, elastic cuffs and hem 11.3 190
Patagonia Down Sweater Polyester 800 down 2 zippered hand pockets, drawcord hem, elastic cuffs 11.0 200
Mountain Hardwear Nitrous Polyester 800 down 2 unzippered hand pockets with flap, zippered chest pocket, drawcord hem, elastic cuffs 11.0 220

Compared to the closest competition, the Rab Microlight Jacket holds up well. Its Pertex Microlight shell is a plus, the down insulation seems to be comparable (see explanation above), and it's a better value. Of course, this is a limited comparison; there are numerous other jackets on the market with different constructions and feature sets.

Overall, the Rab Microlight Jacket is perhaps a little more versatile than many of its brethren because of its medium level of insulation, trim fit, lack of a hood, and its pockets. This combination allows the jacket to more easily be worn as either an outer layer or midlayer, in a variety of outdoor sports, as well as for sport-casual dress. However, its numerous horizontal seams allow down fragments to exit. Also, the binding on the hand pockets does little to keep items from falling out; I would prefer to see an elastic piping like that used on the jacket's cuffs and hem.

Specifications and Features


Rab (


2009 Microlight Jacket


Full zip hoodless jacket


Outer shell 30d 1.3 oz/yd2 (43 g/m2) Pertex Microlight with DWR finish, lining is a generic 30d downproof nylon


4.4 oz (125 g) of 750+ fill power down


Measured two layer loft is 1.5 in (4 cm)


Sewn through construction with 1.5-inch horizontal quilting, down filled stand up collar, full front #45C YKK zipper with one slider and storm flap under zipper, two hand pockets, one zippered chest pocket, elastic cuffs and hem, 1.25-inch dropped tail, jacket stuffs into its chest pocket


Size Large tested, measured weight 11 oz (312 g), manufacturer specified average weight 11.3 oz (320 g)




"Rab Microlight Jacket Review," by Will Rietveld. (ISSN 1537-0364)., 2009-11-03 00:05:00-07.


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Rab Microlight Jacket Review
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Julian Thomas
(jtclicker) - F
Re: Rab Down fill-power on 11/10/2009 05:56:00 MST Print View

true! but it is light and rated at -5 - enough for me!

Diplomatic Mike

Locale: Under a bush in Scotland
Fill power on 11/10/2009 06:02:45 MST Print View

PHD gear does have a good rep, but their lack of info stops me buying their gear. Even if you email them to ask how much down they use in a particular garment, they won't tell you.
It's just my gnarly nature. I want to know what i'm buying, especially if it is very expensive!

Julian Thomas
(jtclicker) - F
Re: Fill power on 11/10/2009 07:15:44 MST Print View

I had the vest, then realised I wanted the pullover and sold the vest to a friend. It is wickedly light and very warm. Nunatak gets a good rep around here, but I've NEVER seen phd stuff shedding down....

Julian Thomas
(jtclicker) - F
Re: Re: Fill power on 11/10/2009 07:17:29 MST Print View

... meant to add. If you do their 'design your own bag' you can specify EXACTLY the quantity of down. If the prices aren't crazy I'll be getting a summer quilt when they launch them - I'm very impressed with their stuff. They are like the MLD of the UK but with worse communication!

Diplomatic Mike

Locale: Under a bush in Scotland
Rab fill power on 11/10/2009 07:21:11 MST Print View

This was a thread about the Rab Microlight review, Julian.
I get the fact you are a PHD fan. ;)

Julian Thomas
(jtclicker) - F
Re: Rab fill power on 11/10/2009 07:50:07 MST Print View

:-) sorry for the hijack!

carlos fernandez rivas
(pitagorin) - MLife

Locale: Galicia -Spain
fill power wars on 11/27/2009 05:32:18 MST Print View

Ok .. I KNOW that it is not a phd thread

But me and my climbing partner have several phd garments and sleeping bags

VERY GOOD products no doubts about

but about the "European 900 fill power" CLAIM ... I have serious doubts about .....

In the last years I bought about (Im not sure)a minimum of 6 down jackets and more than 14 sleeping bags for me and (mainly) close friends coming for very good manufacturers as phd, nunatak, western mountaineering, yeti poland,marmot, diamir (spanish brand) and laila peak (spanish)

Honestly I can´t notice the difference with, as an example, other western mountaineering or Nunatak garments/sleeping bags that I own/owned

All of them are REALLY GOOD products (notice capital letters ;-)

As many brands does ( and did before) is a temptation claim that you have the "best down" because is the easiest way to be "the best"

Maybe for that reason the only way to make a difference is to claim "highest fill power"

real or not ......

Edited by pitagorin on 11/27/2009 05:40:56 MST.

Kevin Lane
Rab Microlight Fit on 04/05/2010 19:28:30 MDT Print View

Can anyone advise how these babies fit?

Kevin (Paddy)