Arc'teryx Atom SL Vest Review

Vests or gilets may be an acquired taste, but they can be very versatile, giving you a quick insulation boost with less chance of overheating or restricting arm movement than a full jacket of equivalent thickness. It'd been years since I wore one, so when the Atom SL arrived just as I was leaving the house for a two-day Munro walk and high camp, I threw it in the pack as an optional extra. For a high output couple of days in a mix of warm spring sunshine, wind and cold night time temperatures it proved absolutely ideal. In fact I ended up wearing it constantly for the 24 hours-plus that I was out on the hill. I've worn it over a T-shirt for cold moring runs; and I'm wearing it as I type this, in a warm office. It's a bit of a go-anywhere layer.

Worn over a light softshell (Alpkit Morphosis) on a very windy spring morning  © Dan Bailey
Worn over a light softshell (Alpkit Morphosis) on a very windy spring morning
© Dan Bailey

Fit

Usefully, the Atom SL comes in both men's and women's fit. I tend to fall somewhere between M and L in Arc'teryx sizing (being a benchmark L in most other brands), and while the size M that they sent has a good active cut on me - going over a couple of light layers with ease without feeling baggy - I do also find it notably short in the body. It's so short in fact that if I reach up, my belly shows (never a good thing); though Arc'teryx suggest climbing as one of its uses, there's no way I could wear this with a harness. However on past experience a size L might well be cavernous on me. We are all shaped differently (maybe I've just got a long body?) but it also looks short in the photos on the firm's website, so it'd be worth trying it on for length before you buy.

The arm holes have a close but unrestrictive fit thanks to the stretch panels  © Dan Bailey
The arm holes have a close but unrestrictive fit thanks to the stretch panels
© Dan Bailey

A very slight drop in the rear of the hem provides a wee bit more coverage at the back. A drawcord that just runs around the rear half lets you pull the fit in tight here too. Up top you get a thin collar that goes only up to about mid height on the neck; this I like, as it makes the vest easier to layer on top of. So many manufacturers seem to want to put a hood on everything, but an ultralight top like this is definitely better without (if you need a hood then I'd suggest you'll want something warmer than the Atom SL anyway).

It's hot work but you still need something over the base layer - what to wear? A gilet of course  © Dan Bailey
It's hot work but you still need something over the base layer - what to wear? A gilet of course
© Dan Bailey

Fabric

The shell fabric is a superlight nylon (something called Tyono 20 for those who need to know). This is almost tissue-thin, but feels relatively tough for its weight, with a mini ripstop pattern. Wind resistance is really good - something I appreciated when walking the seven Munros of South Cluanie Ridge in a relentless wind (the forecast said 30-40mph). A DWR finish seems like it'd be enough to shrug off a passing light shower. I've not yet used it in wet weather, but on a quick and highly scientific bathroom test I managed to make it wet out fairly rapidly, so the Atom SL will want to be paired with a shell in damp conditions.

Outer shell fabric and stretchy insert   © Dan Bailey
Outer shell fabric and stretchy insert
© Dan Bailey

Inside - stitched insulation and fleecy stretch panel  © Dan Bailey
Inside - stitched insulation and fleecy stretch panel
© Dan Bailey

Side panels, from the armpits down, are a very stretchy fleecy stuff called Torrent 190, a mix of polyester and elastane, with a treatment to reduce bad smells. These panels help make the Atom SL really comfy and unrestrictive while still being close-fitting. Arm movement is good, and thanks to its stretchiness the cut doesn't feel at all tight at the armpit even though it's cut pretty close. This fabric is not billed as being wind resistant - in fact you can feel it blowing straight through - but I've found it is placed exactly where you want ventilation, so that air-permeability is a good thing.

With a robust zip and ripstop fabric, it feels durable for its micro weight  © Dan Bailey
With a robust zip and ripstop fabric, it feels durable for its micro weight
© Dan Bailey

Fill, weight and warmth

For minimum bulk and maximum comfort in warmer weather, Arc'teryx have used a very small amount of insulation in the Atom SL. The fill is something called Coreloft Compact 40 insulation (40g/m²), a 100% polyester fibre. Apparently this is a:

"Highly crimped, multi-denier siliconized polyester yarn that has undergone a special process which reduces the thickness of the material by 50%, without reducing its insulation value by the same amount."

Cold for camping - I wore the Atom SL all night  © Dan Bailey
Cold for camping - I wore the Atom SL all night
© Dan Bailey

After reading that several times I'm not much the wiser, but I'd have to say it seems to be pretty good stuff. For a gilet that weighs only 160g (size M, as weighed on my kitchen scales) and that feels significantly thinner than any other synthetic insulated jacket in my gear stash, the Atom SL is surprisingly toasty. It's hard to quantify how warm it is of course, and it clearly can't substitute for a fleece or a standard synthetic duvet jacket. Look at it as a super-light and extremely packable extra warmth booster in a winter layering system, or as something to wear on top for high energy activity in cool-ish weather, and you're on the right lines. As you'd hope from a piece that can be worn either on top or somewhere in the middle, it seems very breathable and quick drying too - I've not yet felt sweaty in it.

Features

In keeping with its minimalist feel, there's almost nothing to say on this count. You get a medium-gauge main zip with a draft-excluding, anti-snag baffle. There are also two good-sized zipped pockets, which sit high enough that you can access them when wearing a rucksack hipbelt (or harness, if you find the body long enough to work with one). And that's your lot.

Pockets you can access when wearing a pack belt  © Dan Bailey
Pockets you can access when wearing a pack belt
© Dan Bailey

Summary

Ultralight and highly breathable, the Atom SL is a brilliant minimalist insulated layer. At only 160g I literally have heavier t-shirts, yet it packs a surprising punch in terms of warmth for its negligible weight. Wear it on top in spring and summer, or as part of a winter layering system - the key strength is its versatility. With a low bulk, and an unrestrictive cut, this vest is ideal for active use. However, watch that hem length if you're intending to pair it with a harness - for me that makes climbing in it a non-starter. If only it'd been an inch or two longer! You're paying quite here a lot for what basically amounts to very little, but the Atom SL is well made, and there's much to like about it.

Arc'teryx say:

Superlight Coreloft™ insulated vest for mid to high output activities. Minimalist insulation for warmer days - versatile, breathable warmth. Ideal for a multitude of active summer pursuits, from rock climbing to trekking.

A lightweight Tyono™ 20 shell delivers durability and wind resistance, and the Coreloft™ Compact insulation is compressible, dries quickly and allows airflow. Lightweight air-permeable fleece side panels provide ventilation with thermal performance. Composite Mapping is used to place materials and insulation in the areas that provide maximum benefit.

  • Price: £120
  • Sizes: S-XXL (men) XS-XL (women)
  • Weight: 160g (size M, our measure)
  • Fabric: Tyono 100% nylon; Torrent 190 polyester/elastane side panels
  • Fill: Coreloft Compact 40 insulation (40g/m²)
  • Breathable, stretch side panels for enhanced comfort and mobility
  • DWR (Durable Water Repellent) finish repels moisture
  • Composite Mapping Technology strategically places each fabric for most effective protection and climate management

For more info see arcteryx.com




24 Apr, 2018

I've been looking at the alpkit morphosis Vs a vapour rise actually. How have you found it, or is there a review coming along soon anyway?

Funny you ask: we've a big summer softshell review coming out in a few weeks. The Morphosis is in that, but not VapourRise (Rab have submitted a softshell with no backer for this review). They both use a very similar principle. I've used Vapour Rise stuff for years and really rate it, and I'm quite taken with the Alpkit version too - but I'm not sure I'll have time to offer you a more detailed like-for-like comparison

24 Apr, 2018

What’s the tent in the pic?

 

It's a Macpac Minaret... and it's ace. Look out for a 2-person tents group test this summer

20 May, 2018

I have the Atom SL Vest and really like it for mild weather activity that can get a little chilly in the morning and evening.  For typical US not-really-alpine summer conditions, I think that a long-sleeve sun-protection hoody, the Atom vest, the Rab Vapour-Rise Flex jacket, and a goretex shell for wind and rain protection will work really well in a combination of conditions when generally mild weather makes breathability during activity one of primary concerns.  Add the very light and compact Mountain Hardware Ghostwhisperer down jacket to the pack and I should be ready for the kind of sometimes-intense afternoon summer storms at altitude  that can blow up in the Tetons and Colorado Rockies.

Caveat: since the vest is very new, I haven't tested this combination in the summer conditions mentioned, but rather in relatively mild winter conditions that I believe are equivalent.

I might add that the vest stays tucked in to my harness; hem length is not a problem for me.