The Cocoon Pullover
The Cocoon Pullover (courtesy, Bozeman Mountain Works)
Gear Guy

Should I get a down or a synthetic ultralight jacket?

I tend to get cold around cp and want to get an ultralight jacket to replace the fleece & two thermals I typically wear. I'm looking at the Western Mountaineering Flight Jacket and the Bozeman Mountain Works Cocoon Pullover. Any suggestions? Chris Santa Monica, CA

The Cocoon Pullover

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As good as today’s pile and fleece jackets can be, they still don’t pack the warmth-to-weight ratio of insulated shells&$151;that is, pieces that have down or synthetic insulation wrapped inside a very light, (usually) nylon shell. They’re simply loftier than fleece, and loft equates with better heat retention. The extra shell also cuts down on wind and evaporative cooling (the heat lost when moisture on the skin evaporates). And, their shell makes them great layering pieces—an outer shell such as a Gore-Tex jacket can slip right over them.

The Cocoon Pullover The Cocoon Pullover

But, what to go with—down or synthetic? Western Mountaineering’s new Flight Jacket ($199; uses high-quality 850-fill down to create a very warm piece that’s still very light, only 10 ounces! And it’s a lot of jacket—the Flight actually could be seen as a very light down parka. Bozeman Mountain Works’ Cocoon Pullover ($179;, on the other hand, uses Polarguard Delta, the newest iteration of that long-popular synthetic fill. It’s even lighter than the Flight (8.5 ounces) but achieves that in part by eschewing features such as a full zip.

Other solid candidates include Moonstone’s very fine Lucid Down Jacket ($160; or Patagonia’s synthetic-fill Micro Puff Pullover ($148;, which are each similar to the Flight and the Cocoon in features and warmth. I use a Micro Puff as a skiing base layer and love it.

Still, for backpacking, I’d go with a down piece, either the Flight or the Lucid. I just prefer down—it’s warmer for each ounce of fill than synthetic. It’s also softer, packs down more easily, and lasts longer. The two downsides are cost and water-resistance. But cost isn’t really a factor here as both down pieces are competitive with synthetic. So what about the water angle? It’s true that down can wet out, at which point it takes forever to dry and doesn’t offer much insulation during that time. But when it rains you were a waterproof shell, right? And even if down does get damp, it takes quite a bit of water to really remove its insulation value.

So go get the Flight—or the Lucid—and stay warmer.

From Outside Magazine, April/May 2021 Lead Photo: courtesy, Bozeman Mountain Works

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