The Xenon X Vest is a synthetic gilet that weighs just 220g. By its very nature it covers just your core, giving no insulation to your arms, but leaving them free instead for whatever demanding activity you're engaged in. It's aimed at alpine pursuits, but can be used across a wide range of outdoor activities.
The first question to ask yourself is: is a gilet for me? Some will find great value in a garment that keeps just the torso and neck warm while the arms go unprotected - others will see it as a warm layer that doesn't quite fulfil their needs. Personally, we rate vest layers such as this highly, and find them a great thermal layer for aerobic activities in cold environments (whether that's walking, cycling, scrambling or climbing).
Rab's effort is superbly light, partly thanks to the impressive materials used in the construction. The outer and inner fabrics are made of the windproof and breathable Pertex Quantum, while the insulation is courtesy of the top-of-the-range Primaloft Gold. Unlike down this won't compress when wet, and so will keep you warm even in challenging conditions.
In use we found it to be superbly warm - and even a little too warm on demanding hikes, even when worn with just a baselayer beneath. With the main zip done up fully the Xenon X traps much more warmth than you'd expect an armless garment to. Consequently it makes a great supplementary layer for evenings camping or bivvying, as well as a light and unobtrusive midlayer for winter adventures.
Storage is very good, with two large hand pockets and a perfectly sized Napoleon pocket - ideally suited to take a map or any other bulky outdoor item (it also functions as a stuff sack). The hem is niftily adjustable by two drawcords, while the main zip is well designed and combines well with the chin guard padding at the neck.
In conclusion: you'll pay a similar amount for some sleeved insulated jackets, but for a highly efficient, intelligently designed and flexible mid-layer this is a top choice.
