Rab Prosar Review – an Ultra Lightweight Down Jacket

Rab prosar down jacket

This superlight Alpine jacket weighs only 371g and can be packed down to the size of a can of beans – but is it any good? We put it to the test….

Why we recommend the Rab Prosar jacket: lightweight; warm; stylish

rab prosar woodsA lightweight down jacket which can be squished down to atomic size has been the dream of hikers, mountaineers and camping folk for many years. Although artificially-made fibres can be used in such jackets, they cannot compete with authentic goose feathers for that perfect sweet-spot of warmth versus weight (or more importantly, density). Unfortunately, the plucking of goose feathers for such products is fraught with animal safety regulations and has become a bit of a hot potato in recent years for clothing manufacturers.

The latest Prosar jacket from Rab solves this problem by using ethically sourced goose feathers satisfying the RDS Responsible Down Standards. This means that when buying a Rab jacket you can be sure that the down and feathers come from birds which have not been subjected to unnecessary harm. If you would prefer to pass completely on the idea of using animal products in a jacket then I recommend looking at the Rab Xenon jacket as an excellent synthetic alternative (and actually slightly cheaper than the Prosar).

Also be sure to check out our independent roundup article of the best down jackets currently on the UK market.

Rab Prosar Jacket - Design

Rab Prosar floorThe Prosar is so lightweight as to almost make you laugh out loud. You cannot begin to fathom how an item of clothing so manifestly skimpy could ever profess to provide warmth – and certainly not in freezing, alpine conditions! In your hands it feels like it’s floating, and at a miniscule 371g it essentially is.

The Prosar is available to buy in three colours. Our example (pictured) came in Ebony which although dark seemed to have a hint of navy blue to it. We like it alot. Alternatively there is a brighter polar blue (not so keen) and a rather sexy Oxblood red available. The ebony Prosar has an orange inner lining which really contrasts the darker exterior very well indeed. There are also other highlights in orange such as the windproof zippers and a couple of Rab logos on the chest and rear neck area. It looks very stylish indeed.

The jacket features an integrated hood which is lined with down and is seductively warm. The presence of a hood may not be for everybody though. In rainy conditions (most days in the UK!), an outer waterproof shell will typically be worn over the Prosar and then you have the problem of having two hoods – do you wear them both and risk feeling claustrophobic and unable to hear the birds singing, or do you try and somehow tuck one of them away. It’s a bit of a dilemma. Personally, I’d prefer to have the hood than not but the ‘double-hood conundrum’ is an important consideration to bear in mind before purchase.

Rab Prosar front

The Prosar incorporates two front pockets, which are uncharacteristically quite high on the jacket. This means that if you wish to keep your hands warm in them, you need to keep your elbows up a bit which can get a little tiring over prolonged periods. If you’re wearing gloves, then this is obviously not relevant, but worth bearing in mind depending on how you’ll use the coat.

The sleeve-ends are elasticated, and the jacket features elasticated toggles at the waist to allow the jacket to be tailored as tight or as loose as the wearer wishes. This is a pretty standard layout, but works well.

On first sliding the Prosar on, you can feel that this is a quality item. Rab sometimes get a bit of stick for being ‘style-over-substance’, but we have never had anything but excellent quality products from them. In any case, what’s wrong with a little bit of glamour when you’re hitting the slopes? The Prosar doesn’t disappoint with what we consider to be a great shaped fit and look from the front, side and rear views.

Rab Prosar - Materials

Rab Prosar sideAs introduced above, the Prosar uses goose-down as the primary insulating material. This is rated by Rab as ‘800 Fill Power’ which is middling on their 650 – 1000FP scale and is an excellent all-round heat retainer. Higher-rated down (850FP and 100FP) is only used on the extreme high-end jackets such as the Rab Zero G which costs almost a third more than the Prosar (but is admittedly excellent). The 800FP is ‘high-loft’ which means it fluffs up well and is also treated to be hydrophobic, – this means that it will act to repel water and so preserve its insulating properties for as long as possible before being swamped.

The down is covered with a shell lining made from 10D Atmos. This is Rab’s ripstop lining which is soft and packable and should be reasonably rip-resistant – we really don’t want to test this though on a £180 jacket! Atmos is a tightly woven technical material using polyamide yarns – this provides a windproof and waterproof layer in theory, although often moisture comes from within in these types of jacket.

Rab Prosar - in Use

I first tried the Prosar during November, with a distinct autumn chill in the air. I wore a thin Helly Hansen baselayer under a Rab Nexus fleece. The Prosar went over the top and I was immediately struck by how lightweight the setup felt. The best compliment I can give the Prosar is that I really didn’t know it was there and yet I felt very comfortable even with the outside temperature around 6degC.

On walking for 30 minutes or so, my heart was pumping and I was feeling very warm indeed. I was able to unzip the Prosar and fleece but not the baselayer which was a little irritating. However, I was certainly warm enough which I guess is the main purpose of the jacket.

My next test was on the following weekend with rain forecast. We set off for a 7 mile walk in the Shropshire Hills and I wore a similar setup but with a Mammut Goretex waterproof shell over the top. By the end of the walk I had remained warm, but water had soaked the bottom of the Prosar as it is slightly longer than the Mammut shell. In addition, on removing the layers, I found that the Prosar was actually damp everywhere – I put this down to sweating internally as well as high humidity in the air. You can’t defy the laws of physics, but the Rab Prosar accomplishes it’s main goal of maintaining warmth in challenging conditions.

On getting home I hung the Prosar up on the stairs and within an hour of central-heating warmth it was dry – I found this pretty impressive and most-likely due to the low density of the 800FP goose down.

Rab Prosar - Packability

Rab Prosar packed upTucked away inside one of the front pockets of the Prosar is a little orange stuff sack. When I first saw it I didn’t think that it was suitable for storing the jacket and actually compressing it into the space is not straightforward! However, miraculously it does compress down as shown in the photograph opposite.

Packed dimensions are roughly 20cm x 10cm which is pretty impressive for what is essentially a winter coat! It should not be underestimated how convenient it is to be able to pack the Prosar into a rucksack without commandeering too much space.

Rab Prosar - Conclusions

When you see the £180 price tag of the Rab Prosar you could be forgiven for feeling a pang of indecision – is any coat actually worth this much of my hard-earned dosh? Well based on multiple tests in reasonable challenging UK conditions, the answer is an unequivocal yes. This is a stylish, lightweight, packable and above-all, warm jacket. It can be kept concealed in a rucksack until required and will be seen as a godsend if your core temperature drops. For us it represents the best trade-off in the Rab down range between value for money, warmth, weight and packability.

For information, I’m 6ft3 tall and an XL size fits perfectly. There is also a Women’s version available with the same features.

9Expert Score

The Rab Prosar is a stylish Winter down jacket. At only 371g you do not even know you are wearing it until you suddenly need to unzip it to let out a bit of heat. We highly recommend adding it to your outdoor wardobe.

Rab Prosar Jacket - Video Review

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