The Xenon X is a comfortable fit, it allows movement and isn't loose fitting. The paneling of the jacket is simple, the previous version had more paneling. The clean design has been made possible with the use of Primaloft Gold Insulation Active. It is designed to keep its form meaning it won't sag. In practice there has been no sign of the insulation moving at all.

Rab‘s specification for the Xenon X is:

Weight: 343g/12oz (estimate)
Pertex Quantum® outer fabric
100% nylon ripstop lining
PrimaLoft® Gold Insulation Active (60/m2 (2oz))
Under helmet hood, lycra bound
2-way opening YKK® VISLON® front zip, internal insulated baffle, chin guard
2 YKK® zipped hand-warmer pockets
1 YKK® internal zipped pocket, doubles as integrated stuff sack
Elasticated cuffs, hem drawcord
Fit: Slim

Rab say it is their classic go-to layer for every adventure. So what I did was took it on some adventures! I’ve had this a while, truth is it should have been reviewed by now but it’s been given plenty of use so I am better placed to put some words to it.

Obviously though the main purpose of the Xenon X is to be an insulating layer, with the Primaloft® Gold Insulation Active being what it is, designed for active use, it is best placed as a layer in the system. When you come to a stop, belay or food break, the Xenon X captures that heat and lets the sweat out, paired up with Pertex Quantum® outer.

I’ve been stood on a very windy belay in the lakes as the lead climber scraped his way up a slimy route (we had to bail off it as it was a slimefest) and had no issues with the cold. In truth I could have done with the same layer on my legs!

On the “breezy” Aberdeen coast I have stood around on many an evening wearing the Xenon X, whether it be on the belay, sat at the foot waiting for my turn or even on the route on particularly chilly evenings. There is very little wear on the Pertex outer.

I used the Xenon X as a mid layer whilst winter climbing, no photos of that as it was hidden by a shell, and it performed well. On colder days, say -10 deg C with windchill, the Xenon X starts to reach its limits. I was starting to look for something a little thicker. That said with the one I have being 337g I have happily carried it to combine with another thinner insulation jacket or vest to keep my options open.

The hood, as it says in the spec, is under helmet, I never used the hood under the helmet but I have used whilst standing around or belaying and it does give a nice warm feeling once it’s up. There are no drawcords so the wind can bellow it a little but, as with the rest of the Xenon X , it is neat and if you can have your back to the wind you are sorted.

The size of the pockets on the Xenon X are a big plus. They will easily swallow an OS map in one a guide book and gloves in the other. Rab are pretty good at pockets, and these are no exception.

The inside pocket works as a stuff sack, with a very handy piece of dyneema for clipping to a harness or pack. There’s not many brands putting something as simple and useful as this on the stuff sacks I have come across yet. The dyneema is also used for a jacket hanger loop.

The elastic cuffs allow for the Xenon X sleeves to be pulled up when climbing or when your too warm. And the double zip to allow expose the belay loop at the harness.

Picture Courtesy of Rab

The Xenon X is a clean, simple, robust and versatile insulation layer. It will protect you from the wind and keep the heat in. I can’t see how it can be improved! A female version is available also.

It retails for £170 but can be found for a bit cheaper with a bit of searching. I will have it at hand on many more outings.