The hot thing these days is keeping cool, as in warmth with breathability. The current crop of jackets featuring lightweight synthetic insulation for all you backcountry workaholics – I'm looking at you, fast and light mountaineering crew – has a new showpiece from Arc'Teryx, the Proton LT Hoody. And bonus: we tested both men's and women's versions, because we've noticed an odd trend lately where sometimes there are significant differences between the two from some vendors. We're happy to report that aside from gender-appropriate fit, there are no feature or performance differences between the women's and men's versions of the Proton LT Hoody.
The Proton LT is billed as a lightweight jacket, and tipping the scale at barely over 13 ounces that's absolutely true. In terms of insulation, however, you should think of it as midweight because that's how you'll feel wrapped up in the variable weight insulation (Coreloft Compact 80 in the body, CC60 in the hood). Put another way, for high-output activities in above freezing temps the Proton LT may be too warm.
This is not to slight it's ability to operate over a wide range of conditions. The Proton LT is definitely in the top tier of insulation pieces when it comes to dumping heat and moisture, as we found while cross-country skiing in low-teen temps. With a thick midlayer, the Proton is easily comfortable standing around at those temps, even for our naturally colder testers. We're just saying it's pretty damn good insulation all the way around, and it really hits it's stride as those temps drop and your workload goes up, especially as you get towards zero degrees F.
In terms of features, we always look first for two things: zipped handwarmer pockets that have enough of a lip at the bottom of the opening so things don't fall out when unzipped, and a nice chin-wrap when the main zipper is all the way up, so the front of the jacket wraps nicely into the hood for the cozy scarf-like effect. Check and check. A spacious zipped chest pocket, elastic wrist cuffs and helmet compatible hood round out the features. One thing left out that we don't miss are drawcords for hem and hood. Honestly we never use them, so we're good to go with that. One thing that would have been nice is a two-way zipper for harness use, but the Proton LT rides at a height where you can bunch it up over your belay device without too much trouble.
Here's another thing to know about the Proton LT: the Fortius Air 20 face fabric is tough as nails, so if you're rough on your gear – now we're looking at you, mixed climbing goons – this is the jacket for you. One thing to be aware of with the Proton LT is the trim fit. If you're normally on the border between jacket sizes, definitely go up. On the Arc'Teryx website they show a 5'11" male model wearing a medium, but our 5'10" tester found the large to be a close but comfortable fit. The difference is likely in upper body mass, just be aware. Overall we're extremely happy with the design and performance of the Proton LT Hoody. If you're looking for a jacket that can be a quiver of one, it should be on the top of your list.