Mountain Equipment makes some bold claims for its Helium range of sleeping bags. Fiona Russell tests one out to see if they are correct.

Mountain Equipment makes some bold claims for its Helium range of sleeping bags. The Helium 600 appeared in our guide to the best sleeping bags for hiking. The brand makes some big statements about the Helium: “Efficiently sized, supremely comfortable and low in weight, each Helium bag offers outstanding all-round performance for backpackers.” It’s rare that I agree with a brand’s superlatives, but in this case, I mostly do.

Price: $469 / £280 (Buy now from Alpine Trek) | Materials: 700 fill power 90/10 duck down; shell and lining: 100% recycled 20D nylon | Temperature: Good Night’s Sleep’ temperature -8°C | Features: women’s Alpine fit with zoned EXL system, slanted box-wall baffles throughout, five-baffle anatomically shaped hood, four-baffle anatomically shaped and offset foot-box, choice of regular left or right zip or left long zip, neck collar with Lode Lock closure, waterproof roll-top stuff sack, storage cube | Sizes: regular (maximum user height 170cm), long (185cm) | Mens Version: Yes

My only quibble is that the bag’s weight is a little off. The women’s Mountain Equipment Helium 600 long size should weigh 950g but according to my scales it’s another 62g. Whilst the waterproof compressible and roll-top stuff sack is excellent is adds a further 64g to the pack weight.

Aside from this, there are a wealth of features I like, including a choice of two lengths and ‘women’s Alpine fit’, which is a cut suited to the female physique with narrower shoulders. The bag also has a higher down density in the footbox compared to the men’s version, plus a zoned system that draws the bag around the body and reduces dead air space inside.

During testing I found this bag to be very comfortable and warm, at least partly because of the highly baffled hood and neck. Fixtures such as toggles, adjusters, elastic drawcords and the neck collar lock system are all of equal quality. In addition, the brand founded the trusted Down Codex certification, which “places animal welfare, quality and sustainability at the heart of every down insulated product”.

The nylon fabrics are 100% recycled with PFC-free DWR. The Helium 600 is in the middle of the range, price-wise, and lightweight but not at the expense of comfort, and it’s a clear Best Buy winner for me.