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  • 2 shockcorded Delrin® poles allow the bivy to open in several different positions from wide open to awning style
  • 3-layer Gore-Tex® Respiration Positive™ laminate fabric was created just for sleep systems—it's both vapor- and gas-permeable
  • Durable and waterproof Hydroseal® coated nylon floor; fully taped seams ensure waterproof protection
  • Removable, tightly woven no-see-um mesh provides lightweight, chemical-free bug protection that doesn't interfere with visibility; height is 20 in.
  • End-opening zipper with a wide storm flap allows easy entry and exit without sacrificing waterproofness
  • High-volume foot section with zippered vent allows sleeping bag to maintain full loft for optimal warmth around feet; height is 14.5 in.
  • Footprint is sized to fit thick sleeping pads for increased comfort
  • Straps keep your sleeping pad in place, preventing the bivy from rolling over during sleep
  • Small mesh pocket holds nighttime essentials
  • 5 stake loops and 3 guyline loops provide ample anchor points
  • Includes Delrin poles and stuff sack
  • Shoulder girth is 52 in.


View all Outdoor Research Bivy Sacks

REI membership


Best Use Backpacking
Seasons 4-season
Sleeping Capacity 1-person
Weight 2 lbs. 7 oz.
Packed Size 4 x 15.5 inches
Bivy Length 87 inches
Shoulder Width 26 inches
Design Type Poled bivy
Rated 5 out of 5 by from I've used this bivy for 15 years. I've slept in this bivy on the beach in GA through gale force wind and rain and stayed dry in a down bag. Because I have it I can bring a down bag in a high moisture environment. The two together weigh less and pack smaller than any synthetic bag of comparable thermal rating. I've used it in AK as an emergency shelter when the big tent is in someone else's kayak, and in the low mountains with a tarp in winter when I just can't carry a tent. It even gets me by when the bugs are really bad, and when bugs and rain are not an issue, it lets me see the stars like no tent ever does.
Date published: 2009-10-21
Rated 4 out of 5 by from Cozy I used the previous version of this product for aprox 8 years and it is just now showing signs of needing replacement. It has really been a great way to go for me. Added a layer of warmth and allowed me to carry light sleeping bag above treeline where I prowl, and made a great skeeter and ant free good night's sleep when down in the forest. Has kept the rain out and for me, breathes nicely and has never been too clammy even when warm out. Just throw the bag off part way and dream on. The poles do a nice job keeping the bug screen or flap off my face. It does however require a little patience to set up, but I really feel it worked well for me everytime I used it, and I can lay back and read comfortably or rollover and write in my journal.
Date published: 2008-04-15
Rated 5 out of 5 by from Lifetime Investment I sleep outside 365 days a year, and half the year in some pretty rugged conditions. Let me tell you this bivvy was the greatest investment in gear I have ever made. I have slept in it 600-700 nights since buying it in every situation from Florida to Alaska. After going through many bivvys, this one has the least problems with condensation. The quality put into outdoor research products is astounding. The zippers have worked flawlessly the entire time, and the floor has never developed holes. However, after abusing it for almost 3 years, the fabric has begun to absorb and leak water. I called outdoor research asking to buy fabric to repair mine, and they SENT ME A BRAND NEW advanced bivy free of charge! That's right: anything you buy from them is guaranteed for LIFE. No joke. This is a company that really cares about brand loyalty. From now on when given the option I will only be buying outdoor research stuff.
Date published: 2013-10-31
Rated 4 out of 5 by from Reliable and "everything-proof." This bivy holds up to everything. Keeps out rain, snow, cold, and bugs perfectly. It's really good at keeping in heat, but the tent-like arch gives enough space to breath comfortably while inside. I use a pretty small pack (38L) which fits into the top of this bivy perfectly, so I can keep my gear dry inside. Only issue is the hood. The solid layer supposed to kind of "lock" into position so that the net allows for maximum ventilation, but the hood constantly slips off and falls over the netting. In hot summer nights with high humidity you'll get probably get a little sweaty. Aside from that, this is excellent for any type of weather. If you don't mind not being able to sit up, I highly recommend trading in your tent for one of these.
Date published: 2014-01-16
Rated 3 out of 5 by from OR Advanced Bivy I do not want to be too critical of this equipment but there are two major problems from my perspective. First, the zipper does not close all the way unless one of the poles becomes disengaged. Once this happens, the height of the bivy is decreased 3-4 inches. Second, a considerable amount of condensation collects on the ceiling. Granted, I was camping in 0 degrees Fahrenheit (-18 C) but a film of ice would form on the entire ceiling which began to drop on my face and sleeping bag throughout the night. This happened with the bivy completely closed on one night and partially open on another night. The company claims this does not happen but they may be referring to higher temps. I have decided to return this product and purchase a one-person tent for this type of camping.
Date published: 2014-01-27
Rated 4 out of 5 by from I love it I love this bivy. I used it throughout 5 years in the army (and 4 since I got out) in the field (no pup tents these days, they issue bivy bags that are okay, a lot of guys buy their own if their units allow using non standard stuff.) I have used it all over the east coast, Sierras, Rockies, Afghanistan, Nepal, and many other places and really love it. What surprises me is that after so many years of using the 2000 version, it still looks pretty new, thats after probably 1000 nights in it. Granted I take really good care of it but seriously, it should be worn out by now. I have used a lot of Outdoor Research gear over the years and I have found that the stuff may not be the most advertised gear on the market, but if you base value on durability and quality they cannot be beat. They redirect what they would spend on marketing towards the product R&D, the product price, and quality control and as a buyer you get more for your money. I am not connected to the company in any way, just a long time satisfied customer. This bag rocks, but the one drawback is condensation and lack of ventilation. You have to leave the zipper an inch or two open to get good ventilation when you have the bag otherwise all sealed up in bad weather. You won't get any leaks thanks to a good storm flap, and no creepy crawleys will get in since you have a bug net, but I do like feeling all sealed in. I am a big fan of bivy bags and have looked at everything on the market, and for the things I like (durability, weatherproofness, durability, lightness, durability, ease of setting up, and again, durability) this is the best I have seen. There are a few (Integral Designs and Black Diamond) that have some interesting bivys but they are more like tents than bivys. If you like using bivys, in my opinion this is the best you can get.
Date published: 2009-12-31
Rated 4 out of 5 by from Good choice for soloing I used this bivvy as a primary shelter for several weeks in South America, including both high-altitude camping and lowland camping. Overall I really liked it, and would use it again without hesitation, but there are some things to be aware of. The most frustrating thing for me is the pole design. The bivvy comes with two poles, and five end pieces (two per pole with one extra). The end pieces have snaps on them, which is how the poles are attached to the bivvy. The problem is once you snap the poles into place, if you move around at all, the poles come out of the snap pieces, and the hood collapses. I'm not sure why the snap ends aren't just permanently attached to the poles. I tried it out, and the snaps easily slide through the material into place. So I think I might just glue the snap ends onto the poles and make it permanent. That way I can't lose the snaps, and they won't come unattached while I sleep. Another potential problem is that the screen gets snagged in the zipper very easily. I'm not sure how to improve on this, but it was very frustrating when, on the first night I spent in the bivvy, I snagged the screen in the zipper, resulting in a 1-inch tear in the mesh. Condensation was definitely an issue, but I'm pretty sure that's always an issue. I didn't have any pooling, but the entire inside of the bivvy became wet every night. It wasn't enough to soak through my sleeping bag, and it didn't adversely effect me at all, but it was something to be aware of. Every morning I would empty out the bivvy and let it dry out. One other issue to be aware of is that for people who are on the large size like me (5'11", 220 lbs) there isn't a whole lot of wiggle room. It's big enough for me to get into and lay comfortably, but if I lay on my side, my shoulder is against the roof of the bivvy. So a person much larger than me would definitely be tight. Also, one other small issue. The stuff sack that comes with the bivvy is exactly the right size, so there is no room for error, it has to pack very tightly into the stuff sack. Which means stiff fingers on a cold morning will probably have a hard time getting everything back into the sack. I just used a slightly larger stuff sack and it was fine. Those are all complaints, but I don't want to make it sound like I dislike the product. I still like it, and look forward to using it on all of my future solo trips. The material is very durable and lightweight. It sets up quickly and easily. It kept me warm. There was plenty of room for my large (77" x 25") rectangular sleeping pad. It's definitely a cool little solo shelter. Oh, also the product image shows the hood arranged in several positions. That is slightly misleading, as there is no way to keep the hood partially open. Gravity pulls it back down. You can open it all the way open, or let it rest in the closed position. It won't stay 30% or 50% open unless you rig up some way to hold it open.
Date published: 2009-11-25
Rated 4 out of 5 by from Great product - nearly perfect I do virtually all of my backpacking in the Sierra and purchased this bivy 14 years ago in order to lighten my load on long trips. It was one of the best gear decisions I have ever made. Originally, I viewed it as an "emergency shelter" to use only in inclement weather. However, I now use it every night. As a sleeping bag shell, it adds warmth to my bag, and any dew that falls ends up on the bivy (which dries quickly once the sun comes up), rather than on my down bag (which is slower to dry). As a shelter from the elements, this bivy is rock solid. I have endured several nights of heavy rain and stayed bone dry with virtually no condensation. On one trip, four inches of snow fell on me overnight in the bivy and temperatures dropped into the teens. Again, I remained warm and dry inside. On that occasion, a small amount of condensation did occur in the hood area from my breath, but that was due to the fact that I had to zip the bivy completely closed to keep snow from blowing laterally into the bivy. Fortunately, it was cold enough that the condensation froze on the hood, so I remained quite dry and simply flaked the ice off in the morning. My only complaint with the bivy (remember this is the 1999 version) is that the hood design is not quite perfect. There are nights when I use the bivy for mosquito protection. In its natural configuration, when the bivy is unzipped and the mosquito net deployed, the bivy is not open enough to allow as much circulation as I would like. I get around this by tying the bivy poles in a more open position using a cord threaded through some loops that are provided. It is workable, but not ideal. The bivy does have a finite lifetime. After 14 years of use, the floor in the head area has developed some tiny holes that, during a recent heavy downpour, did allow water to seep through the bottom. That was mostly my fault, as I chose to sleep in a slight depression on a slab of granite (there were no clouds when I went to sleep...the storm came up suddenly in the middle of the night), and I was literally sleeping in a puddle. For that reason, I have retired the bivy and ordered a new "OR advanced bivy." I did notice that the specs on the new model indicate it weighs 2 lbs 7 oz, and so is a little heavier than my 1999 model, which weighed slightly under 2 lbs. I am curious to see if the added weght has to do with a change in floor materials. All in all, I highly recommend this product. Indeed three friends have all purchased this bivy based on my recommendations, and all are happy with the outcome.
Date published: 2013-04-14
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Will these provide any additional warmth over a sleeping bag and liner?

Asked by: Michael R
This bivy sack will keep the wind and rain out but it is not insulated, so it is not rated for providing extra warmth.
Answered by: REIservice
Date published: 2016-11-08

What's the difference between the Outdoor Research Advanced Bivy & and Outdoor Research Alpine Bivy, if any?

Asked by: FrozenTreats
The Advanced is 3" longer, 7 oz. heavier and has a second pole. The second pole allows this bivy to open in several positions.
Answered by: REIservice
Date published: 2017-04-13

I have a "large rectangular" Sea to Summit Comfort Plus Pad. Will that fit inside this bivy? It is 80" long, 26" wide.

Asked by: Mountain Backpacker
Probably not. This bivy is 26" at the shoulder and tapers down to 19" at the feet. A 20" wide pad would be better. If the 26" wide pad was used, it would curl up around the legs and feet.
Answered by: REIservice
Date published: 2017-04-09

The pack size listed is 4" x 15.5" - can this be compressed using a compression sack? I would assume, "no" because of the poles needed, but If it can be compressed - how much compression is realistic and what compression sack would you recommend for it?

Asked by: songwriting
The fabric portion of the Outdoor Research Advanced Bivy Sack can be put in a compression sack and the poles packed separately. A six liter compression sack (or slightly larger) will work out fine.
Answered by: REIservice
Date published: 2017-04-06

Is the bivy sack a mummy style? What size sleeping bag will fit in it? I'm a little larger than average.

Asked by: Luna Dog Mom
The Advanced Bivy Sack is more of a mummy style. A mummy-style sleeping bag will be the better fit for the bivy. The length of sack will be 87 inches with a shoulder girth of 52 inches.
Answered by: REIservice
Date published: 2017-04-09

What make this one 4 season? Also,why is it so much over the other ones?you need to come down on everything here by at least 50%.i can't afford to shop here.That's why I never bought anything here yet.

Asked by: jeremy1976
This bivy is completely waterproof and offers protection from the wind and precipitation, making it a 4 season option. It is the most expensive in our collection because it’s made with Gore-Tex Respiration Positive material and offers features not included with other bivy sacks.
Answered by: REIservice
Date published: 2017-04-09

Will this bivy accommodate the large Therm-a-Rest NeoAir XTherm Sleeping Pad?

Asked by: Michael R
Yes, this bivy can accommodate the large Therm-a-Rest NeoAir XTherm Sleeping Pad.
Answered by: REIservice
Date published: 2017-04-09
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