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  • Rab - Ascent 900 Sleeping Bag: 0 Degree Down - Chili Powder

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  • Rab - Ascent 900 Sleeping Bag: 0 Degree Down - Chili Powder

Rab Ascent 900 Sleeping Bag: 0 Degree Down


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    • Chili Powder

    10 Reviews


    Keep your ascent ultralight.

    The ultralight Rab Ascent 900 Sleeping Bag boasts an incredible warmth-to-weight ratio and protective features for ultralight backpackers and campers alike. Rab's proprietary Hydrophobic treatment protects the 650-fill duck down from moisture to keep you warm through rainy nights, and the windproof Pertex Microlight shell is surprisingly durable for how light it is. The bag's semi-rectangular shape is roomier than standard mummy bags, and an angled footbox offers extra room so your feet don't feel squished. The Ascent also features an internal collar and a drawcord at the hood to seal out any cold drafts, and a zippered stash pocket that's perfect for headlamps. It comes with a full-length zipper on either the right or left side, and a compression stuff sack for backpacking and a cotton storage sack to keep the bag prime for years.

    • 0° F temperature rating
    • 650-fill duck down with Hydrophobic treatment
    • Semi-rectangular shape, angled footbox
    • Pertex Microlight fabric
    • Internal collar and drawcord for hood
    • Left or right sided zippers available
    • 3 pounds, six ounces: ultralight
    • Internal zippered stash pocket
    • Compression stuff and cotton storage sacks included
    • Item #RAB001D

    Tech Specs

    30D Pertex Microlight
    650-fill duck down, Hydrophobic treatment
    Draft Collar
    left, right
    Max User Height
    [regular] 6 ft 3 in, [extra long] 6 ft 7 in
    Shoulder Circumference
    Hip Circumference
    25.5 in
    Foot Circumference
    19.5 in
    Bag Length
    [regular] 7 ft 2 in, [extra long] 7 ft 6 in
    Fill Weight
    [regular] 31.7 oz, [extra long] 33.9 oz
    0 F
    Stuff Sack
    yes, compression
    Storage Sack
    yes, cotton
    Claimed Weight
    [regular] 3 lb 6 oz, [extra long] 3 lb 8 oz
    Recommended Use
    ultralight backpacking, camping
    Manufacturer Warranty

    Tech Specs

    • Reviews
    • Q & A

    What do you think about this product?

    Have questions about this product?

    Great cold weather bag!

    • Familiarity: I've put it through the wringer

    We have had our bags about 3 years and they’ve held up well. We backpack & are happy with the size and weight of this bag for the warmth it provides. We’ve used this bag so far in temps as low as 14 degrees and have been pleased with the results. Love that it gives the option to zip together with my husband’s bag.

    Snug! For my usual conditions anyway...

    • Familiarity: I've used it several times

    I am a thin-skinned Californian that freezes at 55F so I've been in the market for a 0F down sleeping bag for a while. This bag caught my eye at the sale price and the weight was a selling point also.

    Although I haven't tested it out in truly alpine conditions, I've slept comfortably in places I know I couldn't have in my old bag (High Sierra in late season, Banff, early season J Tree) and I would recommend RAB in general to any of my outdoor enthusiast friends. There were times I've woken up to cold dew and FROST on my bag when I've been bivvying but the water resistant treatment does the job.

    Because the bag was an investment piece for me, I haven't 'put it through the wringer' -- unless you count the times I've had to pack it down for backpacking ventures. Either way, the bag regained its shape fairly quickly after being laid out for half an hour.

    Hand Filled in Derbyshire

    Sleeping bags are firmly where we started and they remain a core part of our range to this day. Back in the 1970's when Rab Carrington was making sleeping bags in Patagonia, he probably didn't imagine that 40 years later sleeping bags with his name on them would be used all over the world in some of the most beautiful yet hostile environments.

    To this day, we hand-fill our down insulated sleeping bags at our factory in Derbyshire, UK. This allows us to know for definite that, by the time our bags reach our customers, they have never been compressed or stored in a way which could be harmful for the down inside. By filling the bags in house, we can be completely sure that every down sleeping bag that leaves our factory will arrive to our customers in the best possible condition.

    Mostly Love It!

    • Familiarity: I've put it through the wringer

    This was my initial review:

    I love this bag. As mentioned below it does compress really well and it's also really warm. Additionally, it's a really soft and comfortable bag. Rab did a great job with the little details such as a hood that perfectly secures my pillow in place even if I toss and turn. I would highly recommend this bag.


    I still love the bag overall. There's only been 1 trip I was slightly cold and that was without sleeping in a base layer. However, the biggest problem I've had with the bag is one of the straps came unsewn at the seem when I was tightening it down. This by itself wouldn't be enough to lower the rating from 5 to 4 stars, however dealing with Rab's warranty has definitely been frustrating.

    After contacting Rab and providing basic information like receipt, pictures, etc. I was told I needed to ship them the compression sack and that it would take 3 - 4 weeks to be returned. For someone that goes backpacking nearly every weekend, this was entirely too slow. I decided to suck it up and buy a compression sack from another company. Obviously this was a bit disappointing.

    very warm

    • Familiarity: I've used it several times

    love this bag it kept me warm when i went to the grand canyon

    and it did get very cold outside it got down well into the single

    digits it came with a compression sack and a big bag so it has room to breath and keep its down in place

    very warm

    Warm enough at Harvard cabin

    This nice red bag kept me warm in the teens/single digits at Harvard Cabin in the White Mountains of NH for 3 nights. I should have brought more than 1 sleeping pad though, my back was the coldest part.

    Note: I slept in my baselayer each night and on the last night in single digits slept in a fleece along with my wet gear to dry out.

    Warm enough at Harvard cabin

    Warm, lightweight and packs small

    • Familiarity: I've used it once or twice and have initial impressions

    I haven't had a chance to use this bag in the environments it's really built for, but have used it on for a few nights camping in CO at 13,000 feet where the overnight temps dropped to about 30 degrees. The bag was plenty warm and I left the drawcord a bit loose so as to not get too warm. It's a bit roomier than other mummy bags, but the insulating value doesn't seem to suffer from the extra air space inside. Looking forward to using it over the winter in Yellowstone and the high Uintas.

    Great bag

    • Familiarity: I've used it once or twice and have initial impressions

    Although I haven't used my Rab sleeping bag in extreme cold conditions yet, I can say that it looks to be a great bag, it's light, has a great fit and is really wide and spacious, useful for big and tall people.
    As cons I can mention the non reversible zipper

    Rab Hydrophobic Down

    In the early days, Rab Carrington built his brand around down insulation, and we still see down manufacturing as a core part of the Rab brand today.

    All of our down insulated products are filled with the highest quality Hydrophobic Down, developed in conjunction with Nikwax. The hydrophobic treatment is applied at source and is seen as the next step in our progression in down manufacturing.

    Pretty Cool Bag...

    • Familiarity: I've used it several times

    I love the fit and that it cinches around my head, creating a pocket for me to use clothes for a pillow. Nice feature. I bought the bag for a winter backpacking trip to the sierras and while it only got down to about 15-25 degrees, with snow pack, I needed to use a silk liner and a wool base layer to make sure I stayed completely warm.

    Keeps me warm

    • Familiarity: I've put it through the wringer

    Great shape, it's a little wider than normal in the foot area, which is great for putting boot liners or clothes in there with you. This bag is just wide enough for me to pull my knees up when changing pants or whatever, a nice bonus!

    As far as warmth goes, the coldest I've got is probably around -15-20C and no problems with keeping warm. Compared to my wife's REI sleeping bag, my RAB feels stronger and repels water better, doesn't leak feathers nearly as bad (I've just started seeing a few sneak out), packs down just as small, and keeps me warmer. Highly recommended

    Oh and the stuff sack that comes with it is way too big... I can compress it down a lot smaller with a smaller stuff sack.

    Yellowstone tested.

    • Familiarity: I've put it through the wringer

    I bought this for winters in Yellowstone. So far I have used it on 3 extended hikes (we had snow and blowing at 10000 ft in May) and 2 bike packing weekends.

    The bag performed great in the cold (15') and was a bit too much for the summer even at 8000 ft. Slept on the pad and just had the bag draped over me.

    I have read that the zippers have issues and I have not had any. I have also had someone borrow the bag for a back country trip and she had no issues and was comfortably warm while sleeping.

    I am going to use this bag for a 3 week bike tour from Bozeman Montana to Tucson AZ in November so I will follow up after that.

    I hate the zipper--but warm at 35F

    • Familiarity: I've used it once or twice and have initial impressions

    I bought the zero degree bag as I always get cold when camping. I used it last weekend for the Ragnar Trail relay. The temps in Snowmass went down to around 35, i had an insulated thermal pad beneath me and i was only just comfortable. I also had to wear my down full-length coat inside the sleeping bag to be cozy. Thus, I don't think I'd ever attempt to sleep in this bag in sub freezing weather. The zipper is also TERRIBLE. I found myself fighting with it throughout the night to get it up all the way. Hard to grab and difficult to slide up (kept getting caught). On scale of 1 to 5 I'd give it a 3.

    Hi Emily,

    That's a bummer this bag didn't work out for you. I've had similar experiences with zippers and poorly filled bags in the past, so I know what it's like to buy something that you're relying on to keep you warm and it doesn't. Have you checked out the Sea-To-Summit Talus TsIII? It's a "1" degree bag aka a 0 degree. I have it's little brother the TsII 14 degree and it's very good for the price. The zipper have a light piece of rigid nylon on the baffle so it doesn't get caught every 5 inches while zipping up. It also has 750 fill duck down that's water resistant. I really like my TsII, thought I'd you give a heads up. If you are feeling rich and never want to fight with zippers again I would look at Western Mountaineering sleeping bags. They are hand made in the US and have +850 goose down fill and are generally the most comfortable bag to sleep in. I have 1 already and i'm looking at getting another.... and maybe another after that. Those are just my thoughts, good luck and stay warm!

    Does anyone have the measurements of this bag when compressed all the way down? (down... ha) Would this bag be sufficient for an AT thru-hike starting in January as far as storage and compression capabilities? This is all around the lightest high quality 0 degree down bag I have found for under $300, but I just need details on its size when packed down. ha.... down.