Mountain Equipment Helium 400 | Performance

This spring Mountain Equipment has completely redesigned its sleeping bag range with a lot of input from down guru Matt Fuller, aka ‘Doctor Down’. You can get more detail in our recent detailed look at the new range, but in brief, the whole range has become simultaneously lighter and warmer.

That’s due to scientific analysis of how much and what density of down to use in different areas of the bag, an improved zip design with a more efficient baffle and the careful use of optimised lightweight fabrics.

The brand’s also brought in some really neat detail features like a cunning magnetic neck opening fastener, that pretty much closes itself, drawcords that you can differentiate between in the dark thanks to different shaped cord and a simple but effective waterproof stuff-sac with a basic air-expulsion valve.

In use, we’ve found the Helium 400 hard to fault. It’s not the lightest design in the ME range – check out the new Firefly if you want ultimate lightweight warmth – but it’s a good balance between warmth, pack size and decent value and really well engineered and designed.

The fill, housed in slanted, box-wall baffles for maximum efficiency and no cold spots, is actually duck rather than goose down, but there’s no tell-tale mallard odour and performance is decent. Goose down, by the way, has become increasingly scarce and expensive, apparently because the Chinese have discovered duvets. Who knew?

Anyway, the bag’s proved a seamlessly effective spring companion. The fit is ME’s ‘alpine’, which is quite slim and athletic, so worth trying if you’re more heavily built and all the new features work as advertised. No issues with the well-shaped, warm foot-box even when we accidentally slept with it pressing on the foot of the inner tent, doh…

The hood’s reassuringly lofted and warm, the magnetic catch is genius. It pretty much shuts itself when the two components get close, stays secure in use, but is easy to open when pulled in the correct orientation.

We also like the differentiated cords for the hood opening. The front one is flat, the back, rounded. That means you can tweak the hood fit in the dark using feel to tell the difference between the cords. It’s a small touch, but a nice one.

W had no issues or cold spots from the full-length, non-snagging side-zip, You can open it from the bottom for venting or just unzip from the top for ease of movement, reading and/or cooking from your bag and so on.

Finally, even the simple, roll-rop, waterproof stuff-sac has been carefully thought out. A simple eyeleted air valve makes it super easy to squeeze out excess air before you cinch it all up and stash it away in your pack. And when you get home, a cunning cube-shaped storage sack makes it easier to pack away under your bed.