The Large cover fits over my Gregory Palisade perfectly and since it has a little extraroom it includes my sleeping pad on the side as well. Great packcover and keeps everything dry

Fits great over my Kelty Comal 3500 pack; Kept everything dry as needed!

This pack cover is great. I've never had any water get in, it packs up tiny, it comes with an attached stuff sack, and it weighs practically nothing.

The XS does NOT have a mid-back keeper strap (that was a surprise when I got mine in the mail). Despite this, I haven't had any problems with keeping the cover on, even while cycling.

The very slippery fabric also makes an excellent impromtu sled on a snowy slope...

I really don't get the point of most pack covers. In a total downpour, there is no stopping the rain from soaking the back of your pack, which pretty much renders the entire idea useless, plus YOU will get soaked. As an alternative, I got myself the S2S tarp-poncho, which is simply a GIGANTIC poncho to cover you AND your pack. No water gets in the back of your pack, and you, yourself, stay dry, too. It looks... ridiculous, but functionally it does the job better than any pack cover could ever do. And in the middle of the wilderness, who cares how stupid you look, right?
Anyway, I gave this 3 stars cuz for what it is, it's made of high quality materials and works... but useless in a downpour. S2S ROCKS THOUGH!!!

I've used this thing a number of times. Some times it works and other times not so much... I think that basically it boils down to a number of factors, some of which may be out of your control. If you can't arrange it in such a way that no water could possibly get, then it wont work. This seems obvious, but imagine real-world conditions: a bunch of sleeping apparatus, some nalgene bottles, maybe some trekking poles or other technical paraphernalia attached to the outside of your very full pack. There are bound to be a few odd bulges that pull the elastic edges away from the body of the pack creating the potential for water to get in. Now imagine that you are up on a ridge in wind and rain - water is flying around practically horizontal...some parts of the pack are bound to get wet despite your rain cover. You basically need to be very careful with the arrangement of your pack and probably use a few dry-bags in additional for your critical items like sleeping bag and extra clothes.

I will say that the form factor, integrated stuff sack and adjustable elastic + velcro fastening system leave very little to be desired, but unless you get the rest of it just right, you'll get your stuff wet.

Also this will be obvious to those of you that use tents but if you get it wet and leave it in the stuff sack for any duration it will be mildew on it - mildew causes the urethane to de-laminate thus totally ruining the thing (I learned the hard way...)

Used on the Inca Trail and in the jungle in Peru during rainy season over an Osprey Talon 33. Worked wonderfully. Had also ordered a Granite Gear Cloud Cover at the same time for the trip (because I could only get one of these due to limited supply). The Granite Gear item weighed the same by specs, but seemed less sturdy and didn't fit as well.

I bought the small size that is suppose to max out @ 3000 cu. in. This more than swallows my Golite Jam2 3000 cu. in. pack when it's fully loaded. The neatest thing to me other than the fact it feels like it weighs next to nothing is that it packs up into its own attached stuff sack...great bonus!

This is crucial/essential gear without a doubt. You can buy multiple waterproof items and stuff sacks etc.. but of course not everything is waterproof and nobody likes soaking wet clothes and poteintial electronics getting wet. The answer, just make sure you have this and before it starts downpouring you will have nothing to worry about. It packs into a small ball for maximal portability, and easily fits over your pack (with approprite sizes). Well worth the money and will really make your day when you reach camp and ALL your stuff is dry not just the waterproof stuff.

This is ideal as a rain cover. It is very lightwegiht, packs up VERY small and works great. No complaints here.