OEX Leviathan EV 900 sleeping bag review: impressively low comfort rating at an impressively low price

A down-filled four-season sleeping bag, the OEX Leviathan EV 900 promises big things for a comparably low price tag

OEX Leviathan EV 900 sleeping bag
(Image: © Craig Taylor)

Advnture Verdict

A warm, reasonably lightweight and packable down sleeping bag, the OEX Leviathan EV 900 is incredibly impressive for the price.


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    Reasonably priced

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    Packs down small

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    Quite light

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    Very cosy


  • -

    Only comes in one (nasty) color

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    Temperature ratings are slightly generous

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Meet the reviewer

Why I Love Camping – Finally time for a brew
Craig Taylor

Craig loves nothing more than pitching up in the backcountry, preferably while taking on a long-distance thru-hike. His adventures usually take place in the hills and mountains of Wales but he occasionally gets away to his beloved Alps. As one of our expert campers, Craig revels in testing camping equipment and knows a sturdy shelter from on that will give up the ghost when conditions become challenging.

OEX Leviathan EV 900: first impressions 

The OEX Leviathan EV 900 is a solid four-season sleeping bag with an impressively low comfort rating for the price. Designed by OEX, which is UK outdoor retailer GO Outdoors’ own, high-end brand, the bag comes with great specs for a low price, and it can often be picked up even more cheaply during one of the numerous sales put on by the Sports Direct-owned retailer throughout the year.


• List price: £270 (£140 with a GO Outdoors membership card)
• Weight: 1,370g / 3lb
• Length: 220cm / 87in
• Fill: 900gsm / 600 fill power duck down
• Comfort rating: -9°C / 15°F
• Compatability: Backpacking, trekking, winter camping

The OEX Leviathan EV 900 has a sleeping bag comfort rating of -9°C (15°F) and a lower limit of -16°C (3°F). It comes stuffed with 900g (30oz) of hydrophobic 600 fill-power ethically sourced duck down, and the shell is made from 20D nylon. Featuring a thick baffle along the length of the side zip, as well as a huge baffle and lofty hood around the top of the bag, it’s built to keep you warm in colder climates – and in my experience, it does just that. 

Weighing 1.37kg (3lb), the Leviathan EV 900 is also reasonably lightweight considering the temperatures this thing is built for. And while there are bags out there that will deliver an equivalent level of warmth at a fraction of the weight, there’s simply no beating it at this price point. Moreover, the bag packs down small, especially if stuffed into a dry sack, comes with a handy internal stash pocket, and the plush inner liner is soft on your skin. At £270 (if bought at full price, £140 with a GO Outdoors membership card), I think you’ll have a hard time finding a bag that delivers a better bang for your buck (even if the color is a bit of a turn off).

OEX Leviathan EV 900: in the field

OEX Leviathan EV 900 sleeping bag

The photos don’t capture the true yuckiness of the rotten yellow color of the OEX Leviathan EV 900 (Image credit: Craig Taylor)

I’ve had the OEX Leviathan EV 900 for a few years now, and I’ve slept in it at varying temperatures in different climates. I’ve always been impressed by its performance, be that on a rainy thru-hike of Germany’s Black Forest National Park, dozens of winter nights in and around Snowdonia’s Glyderau, or 10 chilly October nights in Wyoming’s Grand Teton National Park. It might have lost a few of its feathers (but none of its warmth) over the years, and has a few small scuffs on the outer, but apart from that, it’s practically good as new – and I’m confident I’ll still get many seasons out of the Leviathan 900 yet.

Truthfully, my only gripe with the bag is in fact the thing that matters least when you’re deep in the backcountry: the color. It’s a sort of rotten yellow. It’s the least appealing color I’ve ever seen. This is obviously not an issue in a dark tent, though I do ask myself why the design team at OEX decided to make this the only option – especially for their flagship down bag.

OEX Leviathan EV 900 sleeping bag

The OEX Leviathan EV 900 has an impressive comfort rating but we wouldn’t recommend bivying in it (Image credit: Craig Taylor)

I also think the testing team was a little generous with the temperature ratings. Admittedly, I’m a very cold sleeper, so I always have to shave off a degree or two when considering the temperature ratings of bags. That being said, a comfort rating of -9°C (15°F) and a lower limit -16°C (3°F) seems excessive. I’d only be confident stretching this bag down to -9°C (15°F) if I had some extra thick base layers and a warm fleece to wear inside it. There’s no way I’d get a wink of sleep otherwise.

Aside from those two things, though, the bag has outperformed all of my expectations. It lofts up quickly even after it’s been stored through the summer, and the 20D nylon outer shell has so far stopped any water from getting into the fragile feathers. Additionally, the zipper along the side of the bag is strong, thick and easy to open and shut, and when operated from inside the bag it rarely snags.

OEX Leviathan EV 900 sleeping bag

The OEX Leviathan EV 900 when stuffed into a dry bag with all the air squeezed out (Image credit: Craig Taylor)

Regarding the size of the bag, I’m 177 cm (5ft 10in) and find that the bag is plenty roomy for me. When it’s warm, I can leave the top open and not cinch everything all the way up. When it’s cold, I can hunker down into the bag a little more, tighten up the baffles and zip everything up full.

As down needs to be left uncompressed during storage, the Leviathan EV 900 also comes with a handy storage sack. Wide and lofty, it lets the bag maintain its size when not in use through the summer. Additionally, it comes with an easy-to-use stuff sack that lets you compress the bag down to a smaller size for easy packing, although I tend to store it in a dry bag when I’m in the backcountry to pack it down even smaller and ensure it doesn’t get wet.

OEX Leviathan EV 900 sleeping bag

The Leviathan EV 900’s compression stuff sack (Image credit: Craig Taylor)
Craig Taylor

Growing up just south of the glorious Brecon Beacons National Park, Craig spent his childhood walking uphill. As he got older, the hills got bigger, and his passion for spending quality time in the great outdoors only grew - falling in love with wild camping, long-distance hiking, bikepacking and fastpacking. Having recently returned to the UK after almost a decade in Germany, he now focuses on regular micro-adventures in nearby Snowdonia and the Brecon Beacons, as well as frequent trips to the Alps and beyond. You can follow his adventures over on komoot.