Proton SL Hoody Women's

This is the unicorn of jackets and I wear it all the time. ALL THE TIME. It is my go to piece for AT, running, hiking, cross country, any high output activity in the winter where I need a little warmth and some breathability. Any time I wear it, which is all the time, the people I am with comment on how awesome it is. Other companies have started to do their own versions, but this is the best. The weight is perfect, the warmth is always good, from 0 to 40 degrees F. And I just vary what I layer with (a t-shirt or long sleeve in merino or tech material), and it's awesome. The fit is great, I am usually a small and the small fits well. I have two because i wear it so often and needed to work more colors in. My older one is from 2020, and it has held up to constant wear, the fabric has withstood a lot of wildnerness and doesn't have a rip or tear. I don't notice a huge difference in fit between the two, as other reviewers have suggested. I have the Atom, and I love that too, but if you're buying one, this is the one. :)

It's an absolute winner! The fit is spot on, incredibly light, and highly breathable—perfect for all kinds of activities. It offers great water resistance with its DWR finish, works as a solid windbreaker, and layers effortlessly. Definitely a piece I’d buy again!

Fits true to size. Very warm for its weight and compactness. Great as a light warm casual layer as well as an active layer for colder ski touring days. Very versatile

The Proton SL is my go-to for higher output activities (mainly ski touring and resort skiing, but sometimes biking and MTB) because of how breathable it is while still providing warmth and protection from cold and weather. The octa-loft insulation is cozy with a nice next-to-skin feel of a fleece jacket (not slippery or clammy like most puffy jackets) making it comfortable to wear with a tank top or tshirt underneath. I typically layer this piece with either a merino tshirt or a thin baselayer like the Taema for high output/cold weather ski tours and resort days. The outer material has good DWR properties and beads water if there is precipitation, and the octa-loft allows moisture to escape quickly keeping the piece breathable. Once you pop a shell jacket on, the jacket still pulls moisture away from your baselayer to keep you dry but warm. The hood is also the perfect size to wear while skinning if it is windy or precipitating to keep my ears warm and head dry. The layer is not too bulky so it fits well under a shell or under bib pants. I've washed my Proton SL quite frequently and haven't seen huge changes to the loft, with the exception of wearing a backpack I have seen some compression of the octa-loft in the shoulder area and upper back where my backpack weight is but this doesn't seem to change it's ability to keep me warm and dry. I am 5'5", 130lbs with an athletic body type and typically wear a size M in baselayers and jackets with Arc'teryx, and I have a M in this puffy jacket in the Proton SL and it fits perfect for layering. If I were to get this as a lifestyle puffy, I'd probably size up to a L for a more relaxed fit. Best mid-layer for high output activity! I hope Arc'teryx continues to make a version of this layer for many many years. Would love to see more color variety besides just the black and white.