Our review of the Mountain Equipment Helium 600:

Mountain Equipment makes some bold claims for its Helium range of sleeping bags, which includes 250, 400, 600 and 800 fill versions, and bags for men and women.

The brand states: “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.

My only quibble is that the bag’s weight is a little off. The women’s 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.

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.

Want to compare this to other similar sleeping bags then check out our comparative test here