MSR AC-Bivy - Ultralight 1 Person Bivy

I've been using this bivy for a couple months now here in Alabama.have used it in cold weather (20F). some condensation at the feet. not much.i slept next to the fire one night and an ember landed on the bag which burned a hole through it.patched it with a tent patch kit which worked great.i have not used it in the rain yet but it seems like it would keep out the wetness.great to sleep in, very comfortable ( i like it better than my hammock now).the floor is very durable.i was comparing this one and the outdoor research bivy. im glad i purchased this one.the only reason im giving it 4 out of 5 is because it burned so easily . . .but thats my fault for getting too close to the fire!UPDATE 8/2/2013well i've had this for a while now and have used it in the forest nearly 20 times now.i've used it in the rain, mud, dry,humid, cold.most of the reviews that give this bag a bad rating are from people who should never have bought a bivy bag in the first place. lightweight bivy bags are not for large humans, Im 5'8" 155. this is who they are made for. they are not for people who MUST be comfortable. they are not for people who get claustrophobic. Bivy bags are for people who just need to keep the rain off,pack small and in this bags case it will also keep the bugs out. I really like this bag. yes its clammy, yes there will sometimes be condensation on the inside.. but try to find a bivy that wont do this. . clammy, close and moist dont bother me, i enjoy it.great bivy for those who like "the bivy way".enduroearth.com

I have a strange relationship with my Bivy, I love the fact that in an emergency, I can jump in this and stay warm, as well as it keeps me protected from most of the elements. I take this with me when ever I am going anywhere by myself.I do wish that there where a couple of differences with it though. I dont like that the only way to keep it off of your face is if you tie the thing up into a tree, or onto a guy line, but it is not free standing. I also dont like that there is no ventilation in the bivy other then if the hood is tied up. I also dont like that if it rains, I need a tarp, just to make sure that I dont get wet. I realize that this is kind of an emergency thing, but for those of us who try to go ultralite while backpacking a little bit of weight vs. getting wet is worth it in my opinion.I really do like this product though, if I am by my self, I dont have to take a tent even when it is nasty weather, I know that I can figure something out. I like that its lite and that I can just stick it in my day pack, and that it doesn't take a lot of room in my backpack. I like the protection from the bugs, and from the elements.

This bivy seems durable and has lasted for over 6 months. It is light and quickly set up. Some condensation builds up as expected. If you have claustrophobia then this isn't for you. I did not need as heavy a sleeping bad when using the bivy as it does a good job of keep heat in. The bivy hood can be kept open slightly to allow for minor air movement around the face. Overall, it works pretty much as the manufacturer describes. I would suggest trying one out, it possible, before buying one. A bivy is not for everyone.

Perfect bivy: light weight, durable, great shape.

Fun bivy sack. However, lots of condensation inside…not sure if this can be fixed with bivys in general. Positives are that it is very light and packs down extremely compact.

Slept in this last night in 40 degrees with moderate rain with a Thermarest mat inside. Sack funnels water straight into the screen and onto your face! Then it goes to the bottom making a nice swimming pool. Good news is it probably does let you go 10 degrees colder in any sleeping bag. If anyone knows how to make this work in the rain please let me know.

I haven't used it outside yet so I can't say how it does in the outdoors (where I can only assume that it is designed to be used) but I tested it inside and I can tell it is well made, (duh, it's MSR after all.)I like that it has an overlapping hood thing over your head as this is the only effective way I can think of to let the moisture in your breath out without letting water in, while using non-breathable materials.This would undoubtedly be about the lightest way to backpack and I could save your life in an emergency.I backpack differently myself however, using a small canvas tarp as a shanty and I love it, because you can sleep right next to the fire, as canvas doesn't burn like all these oil based product do.

I have had one of these before but lost it. Good product, fast service

Für das Gewicht wirkt er sehr robust. Konnte ihn bisher nur bei leichtem Regen testen, aber das ging gut. Leider gibt es sehr starken Kondenz obwohl der Stoff ja eigentlich (etwas) atmungsaktiv sein soll. Jedoch kann es sein dass es aufgrund der geringen Zirkulation tatsächlich normal ist.

This bivy may serve well as an 'emergency shelter' for the 'minimalist' hiker or cyclist as some reviews have indicated. In my case, I found it disappointingly difficult to get in and out of, especially at night. The zipper is quite flimsy. I did not find that it did much in the way of 'raising the temperature' of my sleeping environment. In addition, the netting, without being tied to something is always in your face. If it were half the price I paid, I wouldn't complain but for what it cost I expected better from an MSR product.