Very satisfied with my pack cover. I stay pretty light so I got a medium, It seems a bit large, but the bungy helps. No problems at all during my last four days of rain.....

I bought the M. The package states that the average weight is 5.3 oz. Mine weighed 7.6 oz. Thats 2.3 oz more than the average, or 44% more. Is there one that weighs 2.3 oz less than the average? Of course not. The packcover is not lightweight...it is a very heavy fabric, and the sizing is enormous. OR is out to lunch.

The trade-off between light-weight gear and adequate performance is perhaps best exemplified in this pack cover. It will get damp. It will form a puddle inside if the pack is left out in the rain for more than an hour. But it sheds enough rain that your packcloth will only get damp but not soaked. I took four backpacking trips of a week each with this cover and each time the material soaked through in about half an hour of rain. I returned the cover because it did not fit my needs, since my ten year old cover both fits better and is more waterproof than this cloth. It might fit your need, though, so don't ignore the tradeoff of dampness versus weight savings. Note that my Osprey Exos 58 (about 3500 cu inches) was far too small for the medium cover, which was sized for an expedition pack. If you go light, get a small size.

It works great. I have an Osprey Aether 70. The large size worked great. It kept all of my gear dry. It is relatively light weight and packs down fairly small. I was very satisfied with this item. It kept my pack dry through a night of down pouring rain and while hiking during the day. I would definitely recommend this item.

I bought the XL size for my Osprey Aether 85 after reading on a discussion forum how huge it was. (The user had actually used it one night as a makeshift bivy.) I liked the idea of a cover with lots of room to spare which could be cinched down, leaving no uncovered spots, and which could accommodate other bulky items I might want to hitch to my pack. Well this one does all that with still more room to spare. It is enormous.

Within reason, I don't see how a pack cover can really be too big -- as long as you can cinch it down. Better to have room left over that you don't use than to not have it when you need it, I think. On a recent week-long trip I used this many times to cover most of the stuff I wasn't using, much of it just tossed in a heap on top of my backpack. It drizzled much of one day and all one night and everything stayed dry. Perhaps the reviewer who reports water getting through encountered much heavier rain. But so far so good in my experience. Time will tell...