We take the insanely light and versatile Arc’teryx Atom SL Vest out for a test run.

Last season I reviewed the great Atom SL Hoody – since I reviewed that it has undoubtably become my most used and versatile jacket. I’ve used it all winter for mountain running (both as a jacket for cold conditions and as a throw on for resting on milder winter days), Alpine days out and rock climbing. I’ve even used it for work on several occasions as this winter I’ve been picking up some work as a PE supply teacher and have been outside a lot! I would say I’ve worn it as a mid layer more than my Fortrez fleece. That’s not to say it doesn’t have its issues – I still feel the jacket would be better with a large chest pocket as opposed to two handwarmer ones but that’s a minor issue really.

With that in mind I was keen to test the new vest version when that came to the office as it looked a great item for stuffing into the pack for spring time mountain adventures. The Arc’teryx Atom SL Vest (or Gillet if you are European) is a super light, highly compressible jacket that you can take just about anywhere you might feel that an extra layer might me needed on those warmer days and as a layered piece on colder ones. I would say the perfect use for his would be from early spring (where I’ve been using it for running and sport climbing days) through to early autumn. On hotter mountain days it will fit into suit about any small space including my waist pack for running and easily into the lid pocket of my climbing pack. It’s insanely light, the stated weight is 155g and my size Medium weighed in at 160g (using the trusty CGR scales) you just don’t know you’ve got it on at all.

I really liked the compressible nature of the vest and that it easily went into small pockets of my running vest. For example the Atom SL Hoody needed to into the back compartment of my running vest along with other items such as waterproofs, first aid kit and emergency shelter. The SL Vest, however, was able to squash into a larger side pocket so I could access it on the go a little easier. I also have a Salomon Advanced Skin 3 belt for warmer, lower level days and the SL Vest easily squashed its that. I could actually get my Arc’teryx Nodin and the SL vest into the rear pocket of that so I would say the Atom SL Vest is perfect as a layer for running.

The Arc’teryx Atom SL Vest is made in the same way as the SL Hoody with the main body and back insulated with the lightest Coreloft insulation Arc’teryx offer. I have always found Coreloft to be a great insulator, it keeps more warmth when damp and dries out quickly. As a UK climber/runner I only own one down filled item (my Cerium LT) which I used for drier climbing days or socially. All my other items are synthetic filled jackets which just seem to work better in the milder and damp UK climate. It has a checked baffling and this helps keep all the insulation from bunching up which can be a problem with more poorly designed products. More reasons to choose synthetic fills is that you can just chuck them in the wash with everything else (no special care is needed really and once dried on a radiator the fill comes up as good as new) and you don’t seem to get any fill leakage that you often find with down.

The outer shell is made from 20 Denier Tyono which is a great, tightly woven and windproof fabric. That means it’s not the most robust of materials so if you are racking ice screws then you are going to rip the fabric, but it has proved plenty durable for most activities such as running, hiking and mountaineering. I’ve been happy to wear it sport climbing but I would be wary of weary it for thrutchy gritstone trad climbing. My Squamish Hoody is made from a more durable Tyono 30 and my Nodin Jacket is made using the same Tyono 20 so when I’m out in the mountains I’ve been using the Atom SL Vest with the Squamish Hoody and for more low level, moorland runs I’ve been combining the Atom SL Vest and the Nodin Jacket. My favourite combination has been the Atom SL Vest and the Squamish Hoody and I’ve felt very protected in all but the most driving rain.

The Atom SL Vest has flat fronted handwarmer pockets and have a slightly higher position than the Atom SL Hoody (which was one of my bugbears) so is very harness and pack friendly. I found that if I undid the pocket zips it worked OK with a running vest on and was fine for stashing gloves or a hat on the move. The ever faithful non locking zip worked perfectly, allowing fast ventilation by just pulling the zip apart and the whole jacket is finished off with a right hand hem cinch to help lock in any warmth and a large reflective Aec’teryx logo on the front. The side panels are made using stretchy Torrent which has a Polygeine treatment to help keep the smell bearable.

So, is it the most versatile mountain vest? Well, it’s certainly up there with the best Ac’teryx offers and it certainly tops some of the vests we’ve tested, I’ve used it all spring (and we’ve had a cold, damp, spring here in the UK this year) for sport climbing, bouldering, indoor climbing, running and hiking and it has never let me down. There are a couple of niggles that I would have liked to see mostly the ditching of the side pockets in favour of a large chest pocket (with a reversible zip and tab for clipping on to a harness) and a little bit of reflecting decal on the back for night runs, but otherwise another great Arc’teryx performance piece that once you own you’ll wonder how you ever do without it.

The Arc’teryx Atom SL Vest comes in sizes S-XXL and three colour options Torreador (red), Nocturn (midnight blue) and Black. The women’s version comes in sizes XS-XL and comes also in three colour options Mauviene (purple), Rad (red) and Black Sapphire.

The SRP is £120 and they are available direct from Arc’teryx and selected retailers.