Rab Generator Alpine

I reviewed Rab’s previous synthetic belay jacket the Photon X back in 2019 and gave it 5 stars so the Generator Alpine had a lot to live up to. Spoiler alert, I was not disappointed. There have been a lot of changes chief amongst them is the lack of weight – the Photon X came in at 678g whereas the Generator Alpine is a mere 555g for a size small with stuff sac.

Referring back to what makes a good belay jacket:

  • It must be warm enough.
  • It must compress well.
  • Easy to get on and off over your climbing kit.
  • A hood that easily fits over a helmet (and your shell hood).
  • Robust – doesn’t need babying on the route.

Warmth: PrimaLoft® Gold Insulation with Cross Core™ Technology. The PrimaLoft® fibres are infused with Aerogel, an ultra-low-density material composed of 95% air that was originally engineered to insulate in space by NASA . Aerogels are some of the lowest density materials ever created and together with being extremely porous they make for exceptional insulators that presumably breath really well too. Despite the significant drop in weight compared to its predecessor the Generator Alpine seems just as warm. I felt totally comfortable sitting on top of the Ben having a brew after a soloing up Coombe Gully in temperatures that were supposed to be around -16°C with windchill (I don’t think they were actually quite that cold). Likewise descending Ledge Route later in the day I comfortably sat around watching the action up in Coire na Ciste while having a bite to eat. On the day that storm Franklin arrived I wore the Generator Alpine on and off whilst climbing with another team from the hut on Curved ridge. I was totally comfortable both stood around chatting and whilst moving – the Generator Alpine is cut well so that you can still climb in it without that Michelin Man syndrome you get with some belay jackets. Once on top of the Buckle the Generator Alpine went on and stayed on till we dropped down and again I was toasty warm in 70+ mph winds with only a 100 weight fleece and shell on underneath. All in all the Generator Alpine seems as warm as its predecessor but at a significantly reduced weight.

Storm Franklin 70+mph and something horrible windchill!

Compressibility: another big win here as the Generator Alpine is packs down really well. In my climbing pack I tend to forgo the stuff sac and just stuff the jacket into any available nook or cranny and it just ‘disappears’ – not far off the packability of a down jacket. The accompanying stuffsac is well built – larg enough for easy stuffing even when damp and with a robust clip in loop. Again it packs smaller than its predecessor.

Cut/Tailoring: Belay jackets by their nature must be loose enough to easily don over existing, often damp, kit but at the same time you may also want to wear them occasionally for a pitch perhaps after a particularly frigid belaying session. The Generator Alpine strikes a good balance here being easy to pull on without being too ‘billowy’ when worn for active duty. I opted for the size small to make it easier to directly compare with its predecessor in the Rab range and to an extent I found the cut around the hips only just adequate with a full mixed rack being worn – I’d be tempted to try a size up but it would be a difficult call to decide. The hem of the jacket uses the tougher fabric on the inside to avoid rack induced snags/holes and double ended zip allows you to unzip from the bottom and then a press stud can be fastened to allow you to belay with the jacket pulled down over your harness for warmth. Sleeves are roomy enough to pull on over gloves and use a velcro wrist fastening, I personally prefer elasticated cuffs but much like Cannon vs Nikon or Shimano vs Campagnolo this is a personal preference and doesn’t detract from the Jacket. I just leave them loosely fastened and never feel the need to snug them down in normal use. Pocket wise you get the ideal compliment from my point of view, two zipped hand-warmers, one chest pocket and a couple of internal ‘drop in’ pockets for warming your gloves. All zip pulls are over sized and have a stiffened loop to make them easy to grab or stick a thumb through if your hands are frozen. The attention to detail reflects Rab’s long experience with belay jackets and especially their affinity to the somewhat ‘special’ needs of the Scottish winter climber.

Oversized and lined cuffs, drop in pockets, double ended zip with hem press stud – it’s like a tick list of ideal belay jacket requirements.

Enjoying a brew watching the action near the bottom of Ledge Route

Hood: The hood works well with all the helmets I tried even coping with the particularly high volume Grivel Duetto. Cord locks are internal and very neat but not so easy to slacken when wearing gloves or battling a hoolie so it’s a good idea to get them set correctly before you set off. Tightening them down is easy enough but I had one day when I could have done with loosening them to get the hood over my helmet more comfortably and it proved a bit of a faff in the wind and spindrift. I noticed the neck baffle has gone compared to the Photon X but it is a minor loss in reality.
Durability Pertex Quantum Pro Diamond Fuse fabric used over abrasion prone areas such as the shoulders and arms feels very light bordering on the delicate but despite being stuffed with little care into sacs, scraped over rock and having axes shouldered it shows not a single hole. The idea seems to be that it gives a very ‘flat’ face to the fabric that is less prone to snags. It would be interesting to find out how much this contributes to the overall weight loss and increased compressibility of the jacket. That’s not to say I’d go thrutching up a granite off width in it (you’d probably expire from heatstroke!) but it takes far more abuse than you would expect.

Overall the Generator Alpine is a step up from its predecessor in almost every way. It is equally as warm yet lighter and more compressible which seems a little like having your cake and eating it. This appears to have been achieved through a combination of the new aerogel infused Primaloft insulation and the lighter face fabric which nevertheless has proved durable. If you’re looking for a Scottish belay jacket look no further!


  • Warm
  • Light
  • Compressible
  • Good cut


  • Internal cord locks a little awkward to slacken with gloves on – fine to tighten.

SRP £250


Disclaimer – CGR reviewers are never paid to provide a review and the website does not take advertising. We are a bunch of keen climbers and travellers that accept sample products and offer an honest and independent review of the item. The reviewer will often keep the sample after reviewing it for both hygiene reasons and more often they’re in no fit state to return!


  1. I would add another essential bullet – it slso needs a womans fit version. However this appears to be another example of Rab discriminating against women (although they ate hardly unique as most UK gear manufacturers too). But it is still disappointing. So I’ll spend my £s on gear by European / Nordic manufacturers that do value me as a customer rather than those that don’t…clearly in Rabs world women don’t do winter mountaineering….

    1. Hi Jade. To be fair to Rab they do produce around 30 women’s fit insulated jackets (https://rab.equipment/uk/womens/insulated-jackets?) however you are right that there is no women’s version of the Generator Alpine. I will endeavour to find out if this is because the boxy fit of a belay jacket is viewed as not requiring a gender specific cut or something else. Out of interest could you point me in the direction of the Nordic/European companies that do a women’s fit synthetic fill belay jacket? I know Klattermussen do a ‘unisex’ fit one but I’m struggling to find/think of any others available in the UK. Thanks Rich

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