I thought this bivvy was going to be a tougher grade of material. Instead it is a super thin nylon similar to a packable running jacket. Not durable enough to use outdoors as a standalone sleep system. Feels like paper. It does pack very small, though.Caveat up front - I have not used this out in the wild yet. At 5'10" and 170lbs, I had no issue getting in and out of this bivvi. it was a little roomy without also using a sleeping inside this bivvi. Some reviews complain that there is no zipper. That's correct, this one has no zipper, but they have a more expensive model that has a half zipper on top and that model is wider at the shoulders - designed for bigger special ops guys. Forgive me for not providing a review of how it performed in some austere and risky wilderness environment, but it's spring 2020 and everyone is in lockdown. I did however try it in my living room. I'm not sure how breathable it is. In the hour I laid in it on the floor watching TV, I could feel heat building and a slight bit of moisture - that's in a 15% humidity environment at 72 degrees F. I have no doubt that it's waterproof because it seems to not let air through the material. As I tried to get all the air out before folding and folding and folding to put it back in the storage pouch, I found there were air pockets (clearly I failed to press all the air out) that did not let the air out as I applied gentle to moderate pressure. That said, it still fit in the storage pouch. The inside has a slight rubbery feel, likely helping the waterproof characteristic and likely hindering the breathability. The outside feels like a fairly slick synthetic material that should help to prevent snags or tears. I tried the cinch string as well. It kept binding. In order to tighten it anywhere close to closed, I had to push the bunched up material away from where the drawstring came out in order to pull the string further. That's no big deal, just a minor detractor. Maybe using grommets where the string comes out might help to prevent the binding. Overall I'm very happy with it. I'll use it as an emergency bag in my hiking pack when I go into the mountains and desert. I'll also take it anywhere that I might camp without a rainproof tent.Solid gear just wish it had a zipperThis biv y is indeed a bit difficult to get in, and out of however, it more than makes up for it in dryness and comfort. I stayed dry and my bag stayed dry the entire night. I will admit that I used this bivy in conjunction with a 8x5 silnylon tarp. That was my whole shelter set-up. Light, fast, compact, and dry.Great for emergencyI returned this because it was to short to cover my head (I'm 6'6" or 78 inches), and this is without a sleeping bag in it. Other wise I would have kept it if I could fit into it. It was advertised as 90.55 inches long. I should have had a foot to spare.Works very well. Thin material packs down well. My jungle bag slides around inside, but not too much.Doesn't keep water or condensation out, so defeats the entire purpose of a bivvy sack... could maybe be used inside a tent, but at that point would be redundant.Comme beaucoup de randonneurs le savent, un bivvi est un excellent compagnon de voyage. En effet, présentant un très faible encombrement (pour celui ci moins de 300g) il permet cependant d enveloppée complètement le sac de couchage afin d offrir une protection thermique et etanche.Il peut s utiliser en complément d un tarp ou d une toile de tente afin de maintenir la chaleur autour de nous ou directement a la belle étoile, protégeant ainsi contre pluie ou rosée du matin.Pour ma part je trouve que le bivvi de snugpak est actuellement l un des meilleurs du marché. Il est vraiment tres petit et tres leger mais par contre la qualité reste vraiment au rendez vous.J ai eu l occasion de l éprouver lors de plusieurs nuit en hamac alors que j etais en voyage en autonomie complète le long du tarn en kayak et je n ai pas eu du tout a m en plaindre.L ensemble des coutures présentent des renforts thermocollés. La matiere du bivvi est tres legere et ne gene en rien les mouvements la nuit lorsqu on dort.Si je peux vous conseiller en plus de prendre un sac a viande (style sea to summit reactor) qui viendra se glisser a l interieur de votre sac de couchage offrant une protection thermique supplémentaire.Cela me permet de voyager (quasi tout le temps) avec un sac de couchage jungle tres leger et tres compact.Si mon commentaire vous a aidé n hesitez pas a me le montrer100% waterproof. I use the DD magic carpet xl as a shelter and sometimes in very heavy rain water finds it way on top of me. It's not an issue at all with this bivvy. It has kept me and my NewDoar ultralite down sleeping bag dry in downpours. The drawcord can effectively be tightened around your face to keep you entirely body from the head down dry as well as allowing you to breath.This bag is not breathable at all. Condensation builds quickly and in the morning the inside of the bag will be quite wet. This has not damaged my down sleeping bag and the bivvy dries off very quickly by turning it inside out and slinging over something to face the wind/sun.I want to get a sol escape bivvy and put it in between this and my sleeping bag. I'd like to see if this helps keep the condensation off my bag (the sol is breathable) and if it helps keep me warmer.At 6 foot I’m just too big for this , if it was raining I would have a hard time keeping my head inside and the draw string is Poorly constructed which is why i won’t be using this ever , what a waste of money, if only snugpak had of giving you a little bit more fabric then it would be a half decent product, but if you shorter it would probably be very good.I've only used it once during a chilly but dry night in Scotland. No condensation, so very breathable. I cannot comment on waterproof ability. It is made of an incredibly light (very finely woven) and strong fabric. I am impressed with the quality of this bivvy bag.Nicely made, keeps moisture out and very lightweight but it was just to small to take my sleep mat, Snugpak Softie Elite 3 sleeping bag and me. The length is fine but the width is not enough for me so i need go purchase another with a square end and not a mommy type for starters.