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  • Arc'teryx - Thorium AR Down Jacket - Men's - Nighthawk
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  • Arc'teryx - Thorium AR Down Jacket - Men's - Nighthawk

Arc'teryx Thorium AR Down Jacket - Men's


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    • Nighthawk

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    Get with the goose down gala in this versatile, lightweight jacket.

    What's good for the goose is good for you, and Arc'teryx joins the feather-fete with its Thorium/Cerium family of jackets. The Men's Thorium AR Jacket is a durable, flexible piece combining goose down and Coreloft insulation to meet your winter outwear demands. Wear it to and from the office, hiking to the final summit of the season, or under a shell while blasting through waist-deep powder in single-digit sunshine. Regardless of how you spend your time, the Thorium jacket protects you from the cold, alone or under a hardshell.

    • Innovative insulator for alpine pursuits
    • Synthetic insulated collar and shoulders keep warm when wet
    • Lofty down insulation in the core makes this jacket packable
    • DWR treated shell sheds snowflakes and light moisture
    • Athletic fit with articulated design for freedom of movement
    • Item #ARC3661

    Tech Specs

    [shell] Colibri (nylon), DWR treatment
    [Down Composite Mapping] 750-fill European goose down, Coreloft 140, Coreloft 80
    Fill Weight
    (down) 3.5 oz
    Center Back Length
    27.6 in
    2 hand zippered
    Claimed Weight
    [medium] 12.7 oz
    Recommended Use
    hiking & camping, skiing & snowboarding
    Manufacturer Warranty

    Tech Specs

    • Reviews
    • Q & A

    What do you think about this product?

    Have questions about this product?

    Trying to decide between Thorium AR and Cerium LT for hiking/backpacking and travel, I also own the Atom LT but I need something for colder days. What would the temp ranges for these jackets?

    Hey Eric, So first -- AR is Arc'teryx way of defining that the jacket is a good "all around" or all purpose jacket. LT stands for Light Weight. The Thorium has 750 grey goose down but the Cerium LT has 850 g white goose down, which essentially results in a lighter weight of filling that still provides just as much warmth. Still, the Cerium LT has 100 g more of insulation, so it is going to be the warmer of the two options. Of course you'll still need a quality base layer depending on where you plan on going, but both jackets are definitely on the warmer side and will certainly keep you warm in single digit temperatures and high winds. Let me know if I can help you find the perfect size!

    I'm thinking about buying this for layering under a technical shell while skiing colder days and ice climbing, does anyone have experience using it like this?


    As far as skiing colder days, I have used this with only a Baselayer under, and a hardshell on top. That has done just fine. On REALLY cold ski days, this with a light fleece+Baselayer, and a technical shell on top does incredibly well.

    Which is warmer, this or the Cerium?

    Which is warmer, this or the Cerium?

    When comparing those two Arc'teryx jackets, I would say the Cerium will be the warmer of the two. This one has an average of 750-fill European goose down where the Cerium is 850-fill European goose down for it's composite mapping. Overall both are solid jackets though!

    Best Answer

    I have worn both of these jackets, and while I would agree with Jared that the cerium feels a little warmer, I think the difference is pretty negligible.

    The real difference between these jackets is a sliding scale of price and weight/durability. The Cerium LT is 8.6oz vs 12.7oz in the Thorium, but you are also paying as much as $60 more.

    The Cerium manages to weigh less and have the same warmth because it employs an 850fill down. But if you are not concerned about a few ounces, you put a premium on durability, and you love the sound change makes when it jingles in your pocket, I would favor the Thorium.

    The weight truly doesn't matter to me. I just want to stay warm. I expect to use this for skiing and for wearing around town. I just want to warmest thing I can find (I hate being cold), without it being enormously puffy. I'll ski with it under my Arc' Gore-tex shell.

    whats gonna be warmer this or my patagonia...

    whats gonna be warmer this or my patagonia down sweater and which will last longer the thorium or the cerium

    Best Answer


    Both the Thorium and Cerium are going to be warmer than the regular Patagonia Down Sweater. The breakdown is Thorium (750fill), PDS (800fill), and Cerium (850fill). However both Arcteryx jackets has a greater fill weight than the PDS and this gives them a strong edge for warmth. Combine that with Arc's new composite mapping that strategically locates synthetic insulation at high-moisture points, and you have two jackets that are very well prepared for adverse conditions.

    Fo durability I would favor the Thorium AR which has a 40D face fabric vs 20D in the Cerium. The Cerium is no slouch, but the Thorium will be able to take more of a beating.

    I wear size M in TNF thunderdown and Dietz....

    I wear size M in TNF thunderdown and Dietz. I like a slimmer fit. What would I need in this Arcteryx?

    Best Answer

    Arcteryx fits similarly to many The North Face products, but is generally more fitted. This puffy layer is an athletic fit, so if the you like a slim fitting piece and Medium fits you in the TNF Thunderdown, I'd recommend staying in the size medium.

    So the Thunderdown is a Regular fit and the Diez is an Alpine fit. This jacket being an Athletic Fit is going to fit more similar to the Diez in the shoulders and arms but its going to be trimmer than both the Thunderdown and the Diez in the body.

    I hope that helps a little.

    Anyone trying this out yet?

    Anyone trying this out yet?

    Best Answer

    I love it. I had the North Face Thunder before and it leaked feathers all the time. The Arc'teryx doesn't leak and is just as warm. They both fit the same but I think the Arc'teryx has a little longer arms. The zippers are better too.

    Everyone is coming up with their own take on moisture management with down jackets these days and especially in the lightweight pieces. The Arc'Teryx answer has been to slip synthetic insulation into those typically high moisture areas (i.e. around the neck and underarms). When I have worn this I have been impressed with its warmth and fit. I think the results are great and while it is puffier than the Cerium LT it still compresses into a Nalgene size.