With a £5-per-year Go Outdoors membership, the OEX Leviathan EV 900 Down Sleeping Bag costs just £169, which is about as cheap as it gets for a four-season down bag. We don’t know of any other better deals on winter sleeping bags across the whole outdoor industry. For this lowly price, you get impressive temperature stats including a –9C comfort rating and a -16C comfort limit grade.
Take these numbers, however, with a pinch of salt. In our eyes they seem a bit exaggerated, but for sub-zero camping a few degrees above or below freezing, the Leviathan EV 900 should keep you warm enough. This cosy warmth comes courtesy of a healthy 900g filling of 600 fill power grey duck down.
The cut has a slight taper in a mummy style, but isn’t too restrictive. You get nice features including a ¾-length zipper, chunky neck collar baffle and a good hood, and the Leviathan weighs just 1,399g and packs down wonderfully compactly.
The negatives? 600 fill power is a low grade of down, which doesn’t loft up as plump or thick as higher grades, and the all-round build quality feels a little cheap compared to more premium products. But at just £169, you really can’t complain – this is still a stone cold bargain.
Pros
- Excellent price
- Good features
- Impressive temperature ratings
- Hydrophobic down
- Lightweight
- Compact
- Classic design
Cons
- Only 600 fill power
- Temperature ratings seem overly generous
- Feels a little cheap
- One size only
- No women’s version
| Price | £169/$214.34 |
| Temp rating | -9C comfort, -16C comfort limit |
| Weight | 1,399g |
| Pack size | 33x25cm |
| Sizes | One size only |
| Fill | 900g of 600 fill power grey duck down |
Temperature ratings
The OEX Leviathan EV 900 has the following EN/ISO lab test temperature ratings: comfort -9C, comfort limit -16C and extreme -38C. These are very impressive stats for a four-season sleeping bag priced at just £169, if purchased with a Go Outdoors membership card (£5 per year).
However, while the EN/ISO lab tests are meant to be standardised across the outdoor industry for reliable like-for-like product comparisons between different brands, these results strike us as a little overly generous. The 600 fill power down doesn’t loft up in a particularly fluffy way – it’s a tad less thick and plump than others, and feels a little flatter and more wadded – and all-round warmth levels feel lower than we expected when looking at the official stats.
Of course, this might all be subjective, but based on our field test experience we’d suggest taking these official stats with a pinch of salt. Rather than fixating on the official -9C comfort rating, we’d recommend thinking of this sleeping bag as warm enough for cold nights a few degrees above or below 0C. But, in our view, we certainly wouldn’t push it towards the double digits of minus temperatures – although, of course, you may cope fine with it.
Ultimately, however, this isn’t an extreme sleeping bag for exceptionally cold nights. If that’s what you need, you’ll probably need to spend a bit more. But for affordable winter camping in milder winter temperatures, rather than the most freezing of nights, the Leviathan EV 900 is a winner.
Insulation type, fill power & fill weight
The OEX Leviathan EV 900 is filled with 600 fill power grey duck down, with 70% down and 30% feathers. 600 fill power is quite a low grade of down and the feather content is high also. Consequently, the Leviathan doesn’t loft up as puffy or thick as more premium grades of down. This negatively impacts the overall warmth and comfort of the sleeping bag.
Having said that, 600 fill power seems appropriate and fair for the bargain £169 price point, so you can’t really complain too much. Furthermore you get a healthy fill weight of 900g of the 600 cuin down, which helps secure the impressive temperature rating stats.
Or, in other words, OEX has prioritised a higher fill weight over a higher down quality, but the end result of either (higher fill power with lower fill weight, or lower fill power with higher fill weight) will be similar(ish), so it doesn’t really matter. Ultimately, 900g of 600 fill power down for £169 is excellent.
The down in this sleeping bag also has a hydrophobic coating. OEX says this coating ensures the sleeping bag is “very practical for winter camping - it retains its loft if it gets damp, so it still keeps you warm in cold and clammy conditions”.
It’s difficult to objectively judge what difference this really makes, but it’s a reassuring thought for the UK’s rainy climate. In terms of ethics, OEX adds that “the Allied Down Feather in this sleeping bag meets the Responsible Down Standard (RDS)”, claiming it is “ethically produced, environmentally responsible and 100% sustainable”.
Pack Size & weight
The OEX Leviathan EV 900 clocks in at a weight of 1,399g on our scales, including its stuff sack (82g). That’s impressively light for a four-season sleeping bag and ensures a good weight saving compared to other heftier bags.
The Thermarest Saros 0F, for example, is 2,408g and the Simond Makalu III is 1,814g. But some premium, super-expensive bags are lighter than the Leviathan, such as the Sea to Summit Spark -18C, which is just 1,255g.
It’s worth remembering, however, that the Leviathan’s temperature ratings seem a tad generous (see above), so thinking it can deliver the same warmth as heavier bags might be an unfair comparison.
When packed way in its stuff sack, the Leviathan is sized 33cm x 25cm. This is lovely and compact, and ensures the bag fits neatly in your backpacking backpack without taking up too much room.
For storage at home, a slightly bigger mesh storage sack (58g) is provided. Using this sack ensures you won’t ruin the insulation’s loft by storing the sleeping bag in a compressed state. Although it’s not the biggest storage sack we’ve ever seen and it does still squash the sleeping bag slightly.
Materials & sustainability
The shell and lining of this sleeping bag are made from 20-denier nylon. These materials feel reasonably durable and hard-wearing, if not excessively so. Similarly, internal comfort levels are decent but not spectacular – it’s quite soft and smooth, but a tad plastic-y. None of the materials are recycled and the all-round environmental credentials of this sleeping bag are not great.
Size & shape
The OEX Leviathan EV 900 only comes in one size and there is no women’s specific version. Its official dimensions are 220cm long by 78cm wide. It has a mummy style with a slight taper towards the footbox, but it’s not an aggressive taper and doesn’t feel as restrictive as some alpine-style bags. There’s a touch more room with the Leviathan. Overall, we’d suggest it’s a standard sized sleeping bag suitable for the majority of users – but if you’re particularly tall, short or plus size, you might want to look for a more bespoke product to your body shape.
Features
Most features you’d expect on a four-season sleeping bag are present in the Leviathan. Down one side of the sleeping bag is a ¾-length zip for simple access in and out of the bag. It’s a two-way zipper, so you open it up from the bottom to create a vent if you’re over-heating.
Underneath the zipper there’s a vertical baffle to help seal out the cold, while at the top of the zipper there’s a small Velcro tab for securing it in the closed position. OEX says the zipper has an “anti-snag band”, but in our experience it does have a slight tendency to ‘catch’ on the shiny nylon lining, but probably no more so than most sleeping bags.
Around the neck is a chunky draught collar baffle, which can be cinched-in via a drawcord to (again) seal out the cold. The insulated hood, meanwhile, is adjustable via another drawcord and the footbox is nicely-contoured and cosy. Internally you get one small zippered pocket, which is handy for storing a headtorch or perhaps some earplugs or similar small items.
Verdict
The OEX Leviathan EV 900 is a 600 fill power hydrophobic down sleeping bag at an excellent price – but the temperature ratings do seem a little exaggerated.
About the author
James Forrest writes regular features and route guides for Trail and has been one of our main gear testers for the last few years. James is based on the edge of the Lake District so when he isn’t off on his latest crazy adventure or challenge, he’s walking in his local fells.