Rating: 5 / 5
This gets a 5 even though it is outdated because for what it is at its weight (created in the early 1990s mind you), at around 1.5 lbs. or 24 oz. (with pole and netting), and for what it does and what it was in its heyday, is great. By comparison with the contemporary BMW NANO and Vapr bivies, this one will only be for really heavy, terrible weather (like pure survival purposes in the vein of the goofy tv show people are talking about on other threads), if used much anymore. In fact, one of the great things about this bag is that it demands attention to detail in its use and knowledge of sleeping system gear in order to use it. So it is a true "technical" piece of gear. In normal, light, but cold and wet weather it can be a question of surviving the bag that is at issue over extended periods, not the weather itself. That all said, it is a great bivy, still today, and I am glad I have it in my arsenal (but nothing can replace the BMW NANO at this point at under 5 oz.)
It has a single pole hoop to hold up the front, zipper closure for the main bag and a zipper bug netting, button snaps to keep it closed in any high winds, and inside are velcro ties to hold down sleeping pad(s) at about shoulder and knee heights. It is thus, except for breathability a very comfortable and usable bivy.
Here is a picture with the entrance open and an old model Feathered Friends Rock Wren II (now the Winter Rock Wren inside, 15 F bag with 2 oz. extra 800 power fill down under an old pre-eVent shell) -- as you will see this is not a breathable bivy or combination of bag and bivy:
I bought this bivy in the early 1990s when looking for lightweight gear. It was state of the art at that time. I bought it at the old, now defunct Moonstone outlet in Arcata, California, for use on the Lost Coast and along the Mattole River, among other places. Nowadays the equipment has improved so that breathability is a functional consideration. At the time GoreTex was one of the best things going and having a water proof and weather proof bivy was a treat. GoreTex was used in all kinds of things and was used in this bivy (still is in the contemporary models). Here it is closed:
It also has stake out ties and a tie at the top to pull it up without the hoop pole. Here is a picture with the bug netting zipped up and the top open for ventilation:
This bag has endured a lot of abuse, and before breathability was an issue we just suffered through any bad weather by leaving it unzipped. In fact, what contemporary readers may get a real kick out of is the WARNING tag on the bag -- which says you can suffocate in it if it is not kept partially unzipped!!
So this review is not to urge buying one of these 'kamakazi' bivy bags, but to give a review of a key piece of gear in the history of the evolution of the modern breathable, or relatively breathable, light weight and UL bivy sacks.
PS: OR was so good that after I emailed them asking about this bivy, they sent me a new hoop pole for free to replace the one I had lost. So this bivy is ready to go into my box of great but outdated, heavier gear -- to be pulled out if facing really terrible weather and don't want a tent. My name for this model is not unishelter or advanced shelter, it is "BombShelter." For the right person, the modern equivalents are functional and great -- but any user has to understand the breathability and, therefore, condensation issues. (That is why it is best used with a bag that is going to be somewhat water resistent or water proof itself.)
Here is the current OR equivalent bag info and picture, from the OR website at:
Many folks use bivies to travel ultralight and others have trouble sleeping with fabric directly on their face. If one of these is you, then this is your bivy. The most exciting innovation in our Advanced Bivy is the combination of a pole over the top at the shoulder position, with a circumferential pole around the head of the sack (pat. #5,458,146). The circumferential pole turns the entire head section of the sack into an awning, so the zipper can be wide open, with the lower edge of the roof several inches off the ground. Rain or snow runs down the roof, off the wide storm flap and onto the ground. If the wind kicks up, the zipper opening can be reduced to prevent moisture blowing in. By adjusting the pole positions on the inside of the bivy, you can vary the size of the opening from roughly a 45° angle to full-on stargazing mode—all with the removeable no-see-um netting in place to keep bugs out. Extra room under the roof is also a great place to store boots, etc., to keep them dry. Sleeping pad straps are included.
Avg. weight: 1 lbs. 15 oz. / 880 g complete;
1 lb. 6 oz. / 625 g without poles & netting
Style #: 40400
MSRP (USD): $279.00
bd (I wonder if it still comes with the warning tag?)