I go on annual treks and hikes, generally in the autumn or spring when routes are not too touristy or busy. Generally I go for mountainous terrain, whether in the Scottish Highlands or the Pyrenees, and this coupled with the time of year that I tend to go at serious wet weather. Until recently I made do with a simple hikers day bag, which has a little waterproof cover that can be taken out and wrapped over the bag. The problem with this design was that it was quite tricky to pull it out quickly in the eventuality of a sudden downpour, and it also occasionally blew off or didn't sufficiently cover my bag, making the whole thing pretty redundant. Eventually the whole thing actually got snagged by a branch and tore – I was not impressed as I was at the time trudging through a very wet Irish wilderness. I remembered that someone who I met on one of my hikes had had a great waterproof bag that they wore just like a rucksack, so I did some research and found this DryBag that I've now used several times. The first thing to be said for these bag is that it is genuinely waterproof and airtight; it has a roll-top seal, which although is a little fiddly to start with, once you get the hang of it is really easy and you will forever prevent your stuff from getting wet. My pack is made from 'PVC500D' (as stated on their website), which so far has been durable enough to withstand a rough scrape of a slide down a craggy rock face (my backside did not fare so well), and the whole thing has also been dropped over a little bridge by accident. After retrieving it I unpacked the whole thing as I was worried that my gear and food had got wet (I was on day 2 of a 10 day trek, and was about 40 miles from civilisation) and thought I should dry it out, but no need! The roll-top seal had worked its wonders and everything inside the bag was bone dry. Another real plus to the DryBag is that you don't need to scrabble with waterproof coverings in the event of a downfall, as the whole thing is waterproof all the time. This has meant that I have now had the freedom to enjoy walking in the rain without worrying about my stuff. Overall I would definitely recommend this style of bag to anyone who is undertaking walking. The full product name is "DryBag Waterproof Rucksack 32L"