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Designed by Mountain Equipment to be one of their lightest bags the Helium 400 will pack down to a compact size yet will still loft beautifully to keep you warm.
Designed by Mountain Equipment to be one of their lightest bags the Helium 400 will pack down to a compact size yet will still loft beautifully to keep you warm.
Mountain Equipment

Mountain Equipment Helium 400 Sleeping Bag - Long - Left Zip

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  • Please send your return(s) to: Returns, Hooked on Granite Ltd, Capel Curig, Betws-y-Coed, LL24 0EN

Mountain Equipment Helium 400 Sleeping Bag - Long - Left Zip


Brand:Mountain Equipment

Code:ME-003539 Me-01286

An incredibly light, versatile sleeping bag that packs down to a compact size making it ideal for cycle touring and backpacking during Spring and Summer.
Designed by Mountain Equipment to be one of their lightest bags the Helium 400 will pack down to a compact size yet will still loft beautifully to keep you warm.
Weighing just 38g/m2, HELIUM™ 20 uses 20 denier yarns to create a fabric that is compressible, tough, and extremely comfortable. Its densely woven construction ensures the highest levels of downproofing, wind resistance and resistance to heat loss. The new HELIUM™ 20 offers greater handfeel over previous HELIUM™ fabrics as well as reduced seam slippage, resulting in even greater durability than the previous fabric.
High-quality duck down has an actual minimum down cluster content of 90% and is Mountain Equipment DOWN CODEX approved, this means you can plug your products unique code into their website to track the source of the down in your bag.
A Trapezium 4 baffle foot piece featuring ME's unique Bulls Eye™ Technology and offset Sharks Toe™ foot that is engineered for their lightest technical sleeping bags. Its baffle construction restricts down migration whilst keeping weight and bulk to a minimum.
Finally, body heat retension is optomised by utilizing slanted box-wall baffles throughout the entire main body of the bag so that meaningful weight is removed from the bag’s structure. On the very lightest models, further weight savings are gained by the use of stitch-through baffles. The use of mid-level side-seams affords great versatility whether the bag is laid on its front or back and this is also reflected in the distribution of fill which, whilst slightly favouring the top side allows plenty of fill to remain in the underside, foot piece and hood.
When it comes to sleeping bags; Mountain Equipment really know their stuff!

  • HELIUM™ 20 outer shell is very light and highly breathable
  • 385g of 90-10 Pure Duck Down with a minimum fill power of 700
  • Alpine fit maximises thermal efficiency
  • Slanted Box-Wall baffles throughout
  • Mid-level side seams
  • 5 baffle anatomically shaped hood
  • 4 baffle anatomically shaped and offset foot-box
  • Full length Gemini™ zip baffle and integrated collar with Lode Lock™ closure
  • Supplied with waterproof roll-top stuff-sack and storage cube
  • Weight : 860g / 30.3oz
Good Night's Sleep Temperature: -5°C/23°F
  • Comfort: 3°C/37°F
  • Comfort Limit: -3°C/27°F
  • Extreme: -19°C/-2°F
Size Guide:
  • Length Inside: 205cm
  • Max Width at Shoulders: 75cm
  • Foot Width: 50cm
  • Max User Height: 200cm
  • Total Bag Weight: 880g
  • Total Fill Weight: 403g
  • Packed Dimensions: 25x21x17cm
Buyers Guide - How to choose a sleeping bag

A good night’s sleep is key to enjoying your time in the hills and vital for physical and mental recovery. Keeping toasty while you sleep is important because your body will naturally drop in temperature during deep rest. There are a multitude of sleeping bags available out there covering a vast price range but if you choose wisely, maintain your bag and store it correctly it could very well keep you snoozing happily for 20+ years.

Choosing the right sleeping bag for you involves asking some key questions included below. To help you understand why they are important simply click through to our full buyers guide to read about the incredible technologies, science, testing and the design involved in getting you a good nights sleep....

- Synthetic or down?

- Men’s or women’s?
- What is a "season" and why do the prices vary so much?
- How do I make sense of comfort ratings?
- Why should a bag “fit” me?
- So do I get what I pay for?
- I brought a “warm” bag but I’m still cold at night.
- What about the environment?

Top tips to make the right choice:

If you can visit the shop to look at them in person this is ideal as not only does it allow you to place bags side by side to instantly see the difference in cut and loft but it also gives you the opportunity to try the bags on. Just like clothing, they are all cut differently and often come in length options so that you can get exactly the right fit for you. These days, however, travelling long distances and meeting face to face may not be quite so straightforward so we are more than happy to talk with you over the phone to discuss which sleeping bag may work best for you. We are all active users of the equipment we sell and we have all had our fair share of miserable nights, that’s why we are all happy to share our knowledge - so that you don’t have to!
Sizing Information
Alpine Fit- Slightly more tapered in the upper body and in the legs than the Mountain Fit this fit maximises thermal performance and minimises weight.

Alpine Sizing:

Women's Regular Fit
Length: 180cm
User Height: 170cm
Shoulder Width: 75cm
Foot Width: 50cm

Women's Long Fit
Length: 195cm
User Height: 185cm
Shoulder Width: 75cm
Foot Width: 50cm

Regular Fit
Length: 190cm
User Height: 185cm
Shoulder Width: 75cm
Foot Width: 50cm

Long Fit
Length: 205cm
User Height: 200cm
Shoulder Width: 75cm
Foot Width: 50cm
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  • Mountain Equipment Helium 400 Sleeping Bag - Long - Left Zip review by Mark, on 11/06/2021 15:19:54

    Firstly I would recommend anyone purchasing a sleeping bag to visit a store prior to buying as you can then get expert advice and try out any amount of bags. I wanted something that would be light and warm enough for Scotland during May 2021. Having used this bag on the Cape Wrath Trail for 14 consecutive days I can honestly say that it was worth every pound spent. I needed a bag that I could compress down to a small size while also offering warmth and comfort this Helium 400 certainly achieved that. The temperature dropped to -3 on one night and I was still comfortable sleeping in boxers and a light t-shirt. At 6 foot in height the long version was exactly right for me, allowing room to stuff wet gear in with me when sleeping to help dry it out. Overall an excellent bit of kit that I would thoroughly recommend to other potential buyers.
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