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OEX Helios EV Hydrodown 300 Sleeping Bag

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Retail Price £170.00 Was £129.99Save 42%

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A very warm, very lightweight 3-season down sleeping bag, packable to a compact size.

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Product code: 15903109 / 321023

A very warm, very lightweight 3-season down sleeping bag, packable to a compact size.

The OEX Helios EV Hydrodown 300 Sleeping Bag's water-repellent duck down fill will keep you safe in conditions as low as -19°C, and comfortably warm in conditions around -3°C.

The 300gsm / 600 Fill power duck down insulation uses a hydrophobic coating to retain its loft in damp conditions, making it more practical than traditional down in the British outdoors.

It comes with a compression stuff sack which allows youto pack it down to a very compact size, making it easy to pack in your gear and carry with you.

It comes with a compression stuff sack to help you optimise packing space - using the compression stuff bag, it will pack down to approximately 24cm x 20cm.


  • Ultra comfort lining
  • Inner pocket
  • Internal wind baffles
  • Anti-snag zipper band
  • Tested to EN13537
49 x 60cm
Backpacking, Expedition, Touring
3 Season
220 x 78cm

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Ratings & Reviews

Overall Rating

3.36 out of 5
22 reviews
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3.36 out of 5


I used on a family camping trip in August although I was warm it didn't feel overly hot either so I don't think it would be good in colder weather. The feathers kept coming out so returned for refund

3.36 out of 5

Not that warm a bag

I bought 2 of these bags a year ago and have used them a few times. On the plus side they do pack down really small and are comfortable to sleep in but they are not as warm as the ratings suggest. Nowhere near it. Last year my Mrs was cold wearing 3 layers underneath when temps dropped to 5-6C in June and my 9 year old son always wears at least 2 layers and is often cold even though we only camp between April and September. Just come back from Lake District and first night temps dropped just below freezing, and I was cold wearing insulated trousers, base layer, polartec jacket and a Rab Continuum Jacket, and my son was freezing wearing 5 layers! I’d say this bag should have a comfort rating of around 8-10C. That’s how cold it was the last few nights and I was fine in just base layers. Wish I’d spent a bit more money and either got lighter and/or warmer sleeping bags

3.36 out of 5

OEX Helios EV Hydrodown 300

Ok so I camp a lot and needed a light weight 3 season bag. This bag seemed perfect.
First one I had leaked down. I'd wake up believing a goose had been in the tent with me.
Go outdoors (Leeds) very kindly swapped it for a new one.
This on I used for two nights on the Dales Way with temps going down to +4*C. Was really cold.
When holding the bag up to the light you could see through it - no down in places - even after vigorous shaking.
Again cannot fault the staff at Go Outdoors, they refunded with no issues (and I up graded to the Rab Ascent 500).
In conclusion - if you want a really light summer bag this could be ok for anything below +6*C I would not recommend.
If planning a trip where the temp is likely to drop below freezing.....good luck!

3.36 out of 5

Lies all Lies

Don't believe the metrics of this bag, it really is not warm. My 10 year old battered down bag keeps me as warm as this does. Had a very very uncomfortable night INSIDE my car at around +1 to +3 degree C. Was wearing thermals, and eventually had to put on a couple sweaters and another pair of leggings. At -3C good luck, at -19C, you'd probably be hypothermic. Not worth the money. I had suspected this before I bought it, and should have known better....

3.36 out of 5


I spent a few weeks looking at various duck down bags and a trip to go outdoors to have a look at this one. On first inspection it looked ok so took the plunge.I took it home and tried it out on my bed and it was clear that the zip wad sticking all the time. The main reason for me to return it was the down wasn't evenly distributed, the underside was extremely thin and the top wasn't much better. The fabric felt cold to the touch and as already said n prvious reviews its only suitable for british summer time and even then im not sure it would keep you warm enough. It might suit some peolpe but for me its definitely not worth £130 by a long shot. Avoid.

3.36 out of 5

A light(ish) summer bag

I can now confirm that this is not suitable for anything more than the English summer. Down is insufficient, is not well distributed or contained and leaks through fabrics.
Do not buy if you want a durable, useful, multi season bag. A £30 summer bag dies the job with a negible weight penalty.
Not sure I can return mine - but looking into it.

3.36 out of 5

Light weight bag

This the first time I’ve used a down bag as I needed to reduce carry weight and pack size, both of which ticked the boxes. It was also on offer so got it at a good price. However, I’ve only used it in this recent warm weather So unsure about its 3 season credentials.

3.36 out of 5


I am beginning to wonder if I had one of a bad batch after reading such contrasting reviews. Took mine on the British Columbia gold trails but was cold every night. A walmart 20 bucks one did a whole lot better and didn't leave me covered in feathers. If I had kept the receipt I would ask for my money back. It doesn't even deserve the minimum 1 star rating.

3.36 out of 5

Not very warm, definitely not 3 season

I bought this bag expecting great things. I think at time I bought it all the reviews on here were 5 stars. I used it on a trip doing WHW late March/early April this year. Each night there were feathers coming out everywhere and by end of trip I had also noticed the eyelet had come loose at draw cord, causing yet more feathers to come loose. I don't feel it baffles up well and at no time did I ever feel warm or even remotely comfortable in it. I subsequently took it back and was given another one. I have since used once in mid May and I am again finding feathers coming loose and I am again not feeling warm or comfortable in it. For my two cents worth, I don't believe it is any better than a two season bag.
I will again use it this week end and perhaps add a further review. If it doesn't perform well again then I may be tempted to return it and ask for money back.
I know all the early reviews for this item were positive but I'm sorry folks, I have to whole heartedly agree with the last 2 reviews. I am not impressed at all.

3.36 out of 5

Not fit for purpose

Used once on Kinder Scout wild camp in mild conditions despite having a great blow up sleep mat and foil mat I was cold all night which came only from the ground on return I hung bag to air and found that the sun shone straight through the bottom of the bag which had almost no down in it the top was fine and before anyone suggests you should shake it up first I've been a serious camper/hiker for 55years so know the drill needless to say this "BAG" was returned
Note it also slips badly even on a mat with non slip patches

3.36 out of 5

Not so toasty

Just returned from a meander around the Peak District, including a wild camp on Bleaklow. Temperatures at night were probably 8 or 9 degrees (C).
This is my first Down bag. It is light, it packs down well and is a good length. Whilst I generally sleep hot, this was not the case with this bag. Using a liner, I was only okay. I didn't need the hood, but it is a good size. Also the bag turns with you - I'm 6' 1" and under 14 st. The length of the bag is good and there is a quality zip.
I expected to be warmer... sleeping with the outer door open to reduce condensation was not great at the temperatures shown. (The 1 season synthetic bag I usually use has performed well in similar conditions.)
Definitely a summer weight bag... and will work well as such.

3.36 out of 5

Keeps me warm

Fantastic light weight sleeping bag kept me warm whilst on a camping trip with friends and packs small so left room in the rucksack for all my other items.

3.36 out of 5

Sounds too good to be true?

I have to say I was a little skeptical about buying this sleeping bag.....and the product description sounded too good to be true. I was looking for something to replace my heavy Rab bag.

I was WRONG, it's a great sleeping back and it really does weigh around 750g plus the stuff sack. It also packs down really small.

I have used it on a couple of bivi/bikepacking trips and it performed really well. A lot of bag for the money, I can highly recommend this sleeping bag!

3.36 out of 5

GO Recommended Product

I will prefix my review by stating that I am an employee of Go. However, I purchased the bag using my own hard earned dosh and my review is entirely honest and unbiased.

I purchased the bag a few weeks ago after seeing it arrive in store. I was in the throws of planning what kit to take on my walk of the Yorkshire Wolds Way. I was intending to go as light as possible and was aiming for a base weight around 9 pounds (4 kg). My intended sleeping option was going to be an Alpkit cloud quilt but I had just bought a Klymit Inertia short sleeping pad and I knew it wouldn't work with a quilt with cold nights forecast.
I bought the Helios because of its low weight, quality feel and pack ability, it is the first OEX product I have owned.
I returned from the walk yesterday and really enjoyed the route. When on a multi day walk and when you are sleeping in a single skin tent, the overall experience is largely dependent upon how you sleep at night. In this, the performance of the sleeping bag is either the hero or the villain of the piece. This OEX sleeping bag was one of the most heroic, outstanding pieces of kit I have ever owned. Given it's relatively low cost I believe it performed as I would expect a premium brand costing double should. In fact, on close inspection it looks like a premium brand bag. It even comes with a large mesh storage bag and a compression sack should you need one for your rucksack.
In use it feels lovely, the materials feel luxurious and the hood and closures work perfectly.
I experienced single digit temperatures most nights and cold winds, I chose to sleep with the tent door open most nights to reduce condensation in the flysheet, despite this I was toasty warm in the bag which lofts beautifully every time.
I could go on, I have no negatives to report, buy one and grab yourself a bargain from the rising premium brand that is OEX.

3.36 out of 5

GO Recommended Product

I looked at this bag as I have the OEX Leviathan and wanted something to be used at altitude when out wild camping through those late spring/summer and early autumn nights out wild camping in the Lakes and Scotland.

I was really surprised by how much I could compress it down using a roll top dry bag and it was way smaller than the size stated on the web. I used it for the first time on Helvellyn in July when the summit temperature was just above freezing with a clear night and a great sunset. Never felt anything through the bag and slept in just a set of Rab MeCo leggings and long sleeve top.

If you want a super light weight easy to pack down bag then you don't have to look much further and since I've used two of my friends have bought exactly the same one. 5 star guys *****

3.36 out of 5

New review after some time

I used this sleeping bag for quite some nights in different conditions. I slept in conditions close to 0 degrees Celsius and it was perfectly warm, sleeping in just a t-shirt and shorts. Is very warm, very light and packs very very small.
BUT there is one thing to take into consideration if you have broad shoulders, I am 6.1 and 210 lbs with an athletic build and at the shoulders level the bag is quite tight when sleeping on my back. If you sleep mostly on your side then you should have no problem with it. I really recommend it!

3.36 out of 5

Sleeping bag

Very good, I tried already in cold condition (close to 0°C) and was excellent. Light to carry and easy to pack in the morning.
Very happy about it

3.36 out of 5

Great priced hydrodown sleeping bag

Good bag & much better than several others costing more,some are still synthetic filled too !
I've only used it one weekend so no idea on longevity,but it kept me warm actually I was sweating which had beaded on the outside & dried off quickly.
I recommend using with a liner it should help keep the bag cleaner & last longer.
As a 2-3 season use in + temps, it's very light,packs really small & should keep anyone warm.
No idea on outright low - temp use I'd doubt the actual minimum ratings though,cos if your going to encounter those I'd simply spend more money.

3.36 out of 5

Great Product

I just bought this sleeping bag, I was looking for a ultralight bag with with around 0 degree Celsius comfort.

The quality is great, it really weights just 750 grams and for this price is really unbeatable. I like the fact that it packs very small, around 17CMx15CM. I really recomand it, if you are looking for a ultralight 3 season sleeping bag, then this is the bag for you.

3.36 out of 5

So Warm - So comfy - So compact

I got this for my bronze DofE expedition as all the other sleeping bags I tried were too small (I'm 6ft 3) and when I tried to compress it for my bag it was too big. But this sleeping bag was long enough, really warm (I was the warmest there by far), it weighed close to nothing and best of all it got really small. Definitely worth the money.


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