I got one of the small ones for inside my rucksack. I used it in very heavy rain and the rain soaked through my rucksack, and also through the Karrimor Drybag. My phone, purse, car keys etc that I had put in there for safe keeping were all wet.
As I say the rain was very heavy - but I thought the point of a Drybag was to keep stuff dry. Just be careful!
I will put the waterproof cover over my rucksack instead next time.
i think there's alot to be said for bin liners too. I will try lining my rucksack with one binliner before packing it and hopefully that'll keep out most of the moisture. I hoped that the DRYBAG would keep things dry! Maybe not?!
I have some Exped drysacks that I use for compressing some of the gear in my pack and keeping types of gear together. I think they're usually pretty good at keeping the rain out, and even helped keep my gear dry when I fell into a stream on the Anglesey Coastal Path. They've not been exposed to really long periods of rain but on the Sandstone Trail it did rain on and off for most of one day without anything inside them getting damp.
If in doubt though its always better to throw the rucksack's raincover over it because one more layer of protection certainly won't hurt matters.
Water is getting through drybags??? How difficult is it to make something water proof? What a waste of money; might as well use a couple of carrier bags - plastic is impermeable no matter how long you soak it for (only the holes present a route in).
Exped drybags do the job. Sometimes you'll see them on sale in Sports Direct ... grab 'em! I rely on them to things dry (including stuffing wet tent into one) and they haven't let me down.
You should be able to fill a good dry bag with water and it won't leak as long as it has 3 good turns on the closure before buckling.
Do remember that Karrimor doesn't exist anymore. Not like it used to. It was a truly great British company, producing high quality stuff. Mike Ashley and his Sports Direct chain bought the name (along with Lonsdale and others) and now put it on all sorts of stuff. The name doesn't much any more.
Sports Direct often sell a set of 4 Exped Sacks (XS, S, M and L size), that's where I bought mine and I think I only paid about £15 for them. They've been well worth it because I've had no problems with them since. Also when I bought my Wild Country Aspect 2 tent the stuff sack was far too large for the tent, so I transferred it into the M size sack instead and now use the tent sack for my exped sleeping mat.