Rab Generator Alpine Jacket | Review - Outdoors Magic

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Down and Insulated Jackets

Rab Generator Alpine Jacket | Review

The aerogel fill, the climber-friendly features, the cut. There's a whole host of things we like about this, the Rab Generator Alpine

Price: £250
Weight: 540g

Down jackets are nice and all, but when you live in a climate that tends to be quite damp, they’re not exactly the most practical option for insulation. That’s where synthetic insulated jackets come in. Find the right one and it’ll basically bring all the same qualities as down with the extra advantage that it won’t let you down when a bit of rain arrives. Case in point: the Rab Generator Alpine. 

Here at Outdoors Magic, we’ve seen impressively warm synthetic insulated jackets in the past, but none have been quite as good as this. It absolutely nails the whole warmth-to-weight ratio thing. This is a super warm jacket that, at 540g, is satisfyingly light and satisfyingly compressible and low-bulk. 

The Insulation

So what’s the secret then? How have Rab got this so right? The answer must surely lie in the clever application of aerogel fibres within the fill. Dubbed the ‘lightest solid material’ known to man, aerogel seems to be the next big thing when it comes to insulation. It’s 95% air after all and it’s already been blasted off into outer space to help NASA insulate electric cables on their space shuttles. 

There’s 133gsm of insulation on the body and 80gsm in the hood. Photo: Eilir Davies-Hughes

These aerogel fibres are mixed together with PrimaLoft Gold synthetic fill here, an impressive enough insulation in itself and one we’ve long-rated here at Outdoors Magic. Light, highly insulating, long-lasting and made from 90% recycled content, there’s a lot to like about PrimaLoft Gold. And it turns out it’s even better when paired with aerogel. 

The Outer Fabric

Then there’s the outer fabric which is made from Pertex’s specially developed Quantum Pro Diamond Fuse. And there’s plenty to say about this too. I’ve gone through this in some detail in the video above, but the gist of it is that it’s a lightweight fabric that’s surprisingly tough. As you can see in the pictures throughout this review of our tester Eilir using this in Snowdonia and the Highlands, it makes this jacket something you can chuck through a fair bit of rough stuff without having to worry too much about it scuffing or snagging.

One of Eilir's adventures with the Generator Alpine in Scotland


While this has many virtues that make it suitable for all hiking and backpacking, it’s actually primarily designed as a belay jacket and the feature set reflects this. The hood, for instance, has a big volume to it so it can be worn over a helmet (or cinched in comfortably around your head too); the main zip is two-way so you can wear the jacket over a harness; the zip pulls, hood toggle and cuffs are all designed to be glove-friendly; there are big dump pockets for gloves or goggles on the inside of the jacket and the handwarmer pockets can be accessed when you’re wearing a climbing harness or a backpack with a hipbelt.

Other features include a wired, mouldable brim on the hood, a toggled hem, an internal insulated zip baffle, a beard guard and there’s a little popper at the base of the zip so you can open up the jacket for a bit of concealed ventilation when you need to. Last but not least, you get a small stuff sack to stow the jacket away inside. All packed up, it’s about the size of a Nalgene bottle. 


Eilir on the left. Will on the right

I’m 5 foot 10 and have a fairly slim build. Eilir is built the same way but at a slightly longer 6 foot 1. We both wore the Size M and were happy with the fit, which is fairly loose, leaving loads of room underneath for other layers. I found it dropped about halfway down my backside when the hem was loosened fully, so I’d say it’s cut quite long. I quite like that about it though as it means you’re less likely to find the jacket riding up and over a harness. The long, articulated arms (a Rab trademark, you could say) also help in that respect. 

I found I could wear a few of my roomier mountain shells over this, but it was a bit of a squeeze underneath some of the more athletically cut shells I tried it with, the 66 North Hornstrandir Gore-tex Pro jacket being one example. More often than not, I found myself chucking the Generator over my waterproof jacket to save me taking it off and letting all my body heat escape. No harm in doing that when it will still do want you want it to do, even in rain or sticky snow. 

Eilir’s Verdict From The Highlands

“Over the past couple of weeks I’ve been testing the new Rab Generator Alpine jacket in some of the worst weather Scotland and Wales could throw at it. At home in Wales, it was rain, wind, and a bit of snow. In Scotland it was gale force wind and snow.”

“Generally, a synthetic jacket will not be as packable or be as light as the equivalent down jacket but I was pleasantly surprised at how well the Rab Generator Jacket could be packed down into its stuff sack. Having it hanging off my harness when climbing wasn’t an issue.

Winter climbs can often last many hours and I was impressed with how warm it was when sitting in the howling wind and spindrift on Ben Nevis while belaying my climbing partner up the last pitch of No.3 Gully Buttress. The jacket has a relaxed fit which is great when wearing it over other layers and the helmet compatible hood works well to keep out wind and weather. The hood is easy to cinch down when not wearing a helmet using the three different adjustment points on the front and rear. The Velcro on the cuffs held up well in the snow and are easy to adjust with thick gloves on.


The three exterior pockets are out of the way of bag and harness straps and the chest pocket is large enough for snacks and a phone. The large zip tabs are a big win and make using the jacket a breeze with gloves on. I would have liked slightly larger drop pockets on the inside for thicker gloves as I found it a bit of a faff to stuff them away on occasion but this was really the only issue I had with the jacket. It’s a great item and one I’ll definitely be throwing in my pack when the weather is grim and there is a chance of getting wet.”

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