Sea to Summit Ultra-Sil Super Light Pack Cover

I've never had a sack-cover before, mainly because my experience of others' raincovers was that they looked pretty flimsy & useless, flew off the bag in high wind (still attached on parts but not actually stopping the rain / hail / snow covering everything!), and didn't actually seem to be particularly waterproof anyway! However, I started venturing into winter mountaineering, in which conditions being wet-through, or having your extra layer being wet-through, could easily be the difference between hypothermia or not! So I started looking into waterproofing options, I thought about drybags keeping the stuff inside the bag dry, but it didn't seem to be so practical in terms of having a heavy leaky wet rucksack lurking on your back.. so I researched raincover options & went for this.. (I do still use a small drybag inside my rucksack for valuables - headtorch, phone, etc., however since I've used this cover I don't think I actually need to at all anymore - no moisture has ever made it through - I guess it's a back-up habit.)Basically it does actually do what it say it should do! It is actually 100% waterproof, and it is extremely durable in comparison to any I've come across before. This is due to (and this is what makes it entirely different to other raincovers) the fabric it's made of; 'Ultra-Sil' is cordura (a very strong rip-stop material) which has NOT been coated with PU or some other waterproofing, but instead is siliconised, meaning the silicon (which is hydrophobic) is completely embedded into the fabric. This means that it cannot be scratched / worn / weathered off. That sounds heavy.. but it's actually lighter than coated nylon (which is often used for other raincovers).Apart from the extremely good fabric, it's also a fantastic fit. It has a strap which fits through the back of your pack (where the shoulder straps are) which is easily undone when you want to remove it, but makes the cover totally stay put, even in extreme weather. The elastic around the edge is much more elasticated than any other I have seen - basically this means that it comes a lot further around your pack than most raincovers, which makes it hugely more weatherproof due to a better fit. Note that this 'better fit' seems to be for all different rucksacks - I bought it for my winter hillwalking 42L 'tall & thin'-style rucksack, which it fits extremely well.. however when I discovered it worked so well I tried it out on my more casual walking rucksack which is 30L and 'short & fat'-style, which it also fits & covers perfectly. On both these completely different size/shape sacks, the same great fit & elastic bit coming much further round the back, very pleased!I was a bit confused about a small hole (manufactured not damage) which comes near the base of your pack when it is fitted! It is definitely meant to be there, it is made with an eyelet & is covered with a fine gauze. It's only small, say 8mm wide tops, but I kind of thought, 'hmm, is this going to let water in, surely this defeats the object?!') Actually it doesn't seem to at all, and I guess it must be there for 'breathability' (in the loosest sense of the word) - i.e. if some water does enter the area between your rucksack and the pack cover (I can't to be honest see how) then it could run / evaporate out of this wee hole! So I guess it's probably pretty useful. Maybe it also keeps the temperature in that area the same as the outside air temperature, discouraging condensation.I actually sit on my rucksack quite frequently, especially in winter when sitting directly on the snow up the top of a munro totally sucks any warmth right out of you. When this is attached to my sack, I sit on it with the raincover directly on the snow & me covering the part that wants to stay dry as it's next to my back when on. It's a great way of insulating myself against the ground whilst still being able to take a well-earned rest during difficult climbing. I've found that it doesn't rip / stretch / graze / tear or even look like it's had any wear afterwards, and it still maintains it's waterproofness, even the wee hole doesn't seem to let moisture in, so my back stays dry & my bum stays warm - great! I think that's a pretty good test for durability. It's now been used on at least a dozen extreme-weather walks & still looks and behaves as new.Oh, it also fits into it's tiny stuff sack easily, it doesn't need to be folded right or anything, it's not difficult to put away at all (or get out in a hurry) and is easy to have handy for unexpected rain/ snow because it's about the same size as my closed fist.In summary, I am extremely impressed with this raincover, and would recommend to anyone to be honest, from those taking the dog out for a wee walk in the rain (who also have a rucksack..), to munro walkers in all seasons, to those undertaking multi-day hikes with bivouac stops in extreme weather.. or even kayakers. I really think this cover will cope with anything you can throw at it, and more. The price is astonishing for this level of flexibility & usefulness!!

Most pack covers are regular nylon coated with a DWR or silicon outer coating to repel the water. This comes with a duability penalty as over time abrasion removes the outer waterproofing leaving the covering vulnerable.The sea to summit ultrasil bypasses this issue by impregnating the nylon throughout rather than spraying it over the top. The result is a robust, water proof pack cover which doesn't lose its proofing over time.Fitting properly is very important - hook the securing strap together before fitting the cover, to get an idea of the correct orientation. Ensure the water escape hole is at the bottom, so any water which gets in can get out. This is very important otherwise the cover acts as a shield, holding in the water and wetting out your pack. Then disconnect the securing strap, fit the cover, then run the strap underneath your shoulder straps across the back and clip in tight.Like all pack covers this needs to be dried out before storage otherwise it will mildew which will undermine its effectiveness.Used this in many torrential downpours and it has always kept my bag dry.

I bought this cover for a 32 litre pack but more often use it on my 20 litre bag. It's oversized for a 20L bag but functions without any problem. Seems to keep my bag dry overall and has a elastic strap that clicks into place near the bottom. This would be better if this was near the top of the cover as I think it would stay on more securely but then again with the cover being easier to pull of from the top you can access the top of your bag if you need to and still have the cover 'attached'. It also has a small drainage hole at the bottom but I don't see the reason for this as water is supposed to run off the slippery silica material (and does).Overall a good item and I will buy another one sometime for my 70 litre travel backpack.

15-30L size. Comes in such a mini,mini stuff sac which felt so solid I thought I wouldn't be able feed it back in after use but it did! Very compact size but does not have the retainer strap mentioned in the description. Presumable this only applies to the larger sizes. This needs to be amended Amazon. Having said that, it's seamless with a fairly strong elastic around the edge to hold it in place. Hasn't been put to the test so unable to state as to its waterproofness or whether it will stay put in the wind. Hence only 4* at this time. Feels flimsy but with care it should prove robust enough as have used waterproof stuffsacs in this fabric and have had no issues.

Bought this to fit on my Osprey Exos 38.It was a little cheaper than the Osprey branded one, and lighter with better features (the securing band)It fits well even with the rucksack jam-packed full and the external stretchy mesh pockets full.It's 'crinklier' than I expected, but looks like it will be very water proof - not had chance to test it yet, will update once I've used it.

Used this item on my hike in Iceland, where I encountered constant rain and misting and wind. The extra clip that snaps across the back of the pack was envaluable. Love the stuff sack that accompanies the cover as well.

Super small and light yet covers my 27 ltr pack with ease and plenty to spare, would think it will cover upto 40 ltr possibly

The pack cover fits my 60 litre bag with spare space unlike some others i have tried. However after using the cover a few times for 3 weeks now. It already has a couple of holes. I think the cover needs to be a bit thicker to avoid this issue. However it does fulfil its primary purpose of being a waterproof cover well.