That's bout all I can say for this sack is WOW!!!! I'm an ol skewler and have recently gotten into the ultralite/lightweight packing in the last year. Been gearing up for the AT next year and have poured over Backcountry.com and Backpacker magazine for tips on what gear to purchase. I've never used a dry sack, ever to be honest, but knew I would need some form of one for at least my sleeping bag. I own the Lafuma X950 Pro so I bought the Small sized event dry compression sack. I haven't tried it out in wet conditions...but after all the gear reviews I have read here and various other places I am confident my bag will be safe from water. However, if you are new to roll top closure bags there is a learning curve; don't feel ashamed to have to conjure up a gear head through the online chat feature here to get some advice on exactly how that works, lol!!! Long story short, once I finally figured out how this thing closes up I pulled my sleeping bag out of its tote bag and stuffed it in my event sack. After kneeling down on my bag with one knee I was able to cinch the compression straps within an 1/8 inch of their maximum. To put it in a nut shell I just cut 6 inches vertical packing height (if I remember my math correctly that wouold be 42 cubic inches altogether since its app. 7 in diameter...may be wrong) from my packing interior of my bag. That may not seem like much but I am only using a 3000 cu. in. pack for the AT so app. 42 cu. in. is a world of difference in this pack. I guess the lafuma pack bag now gets duty for something else that doesn't need water protection. Some people may think the price for this item is steep, but to me it is worth every penny just for cuttin down on packing volume, I'll say it again, "WOW!!!!" If you're interested in this then I highly recommend because these compression straps haven't budged one bit and loosened up since I cinched it all down...nice!!!!! I will be getting more of these for my clothing and electronics.