Mountain Equipment
Mountain Equipment Helium 600 down sleeping bag
Best use
- Made for
- Backpacking and wild camping
Why these labels
- Backpacking and wild camping: The maker states this use, and the published specs do not rule it out.
From the maker's stated use and the published specs.
- Summer wild camp: 5/10 UK, roughly May to September, nights above about 8 °C, sheltered pitches.
- Three-season hills: 6/10 UK hills in spring and autumn. Wind, rain, and nights near freezing.
- Winter camp: 8/10 UK winter or high ground. Below freezing, strong wind, possibly snow.
- Weight: 6/10 How much it adds to your pack, compared with the whole market.
Comfort -5 °C, limit -11 °C (EN 13537).
Lowest price we found
£299.99 at Ultralight Outdoor Gear
Go to Ultralight Outdoor Gear Compare 3 shopsCold spring, autumn and early-winter camps in the UK hills, down to about -5 °C comfort
- Comfort
- -5 °C
- Limit
- -11 °C
- Fill
- 700 fill down
- Weight
- 1.03 kg (Regular)
Packed size 11.5 L, 25 x 23 x 20 cm Compare with a 2-litre bottle
About as long as a 2-litre bottle and about twice as wide. Drawn to scale.
Where to buy
Ultralight Outdoor Gear £299.99 In stock. Free delivery.
View at shop: Ultralight Outdoor GearAlpinetrek £342.90 In stock. Free delivery. Price shown before a colour or size is chosen; delivery time 5-7 working days.
View at shop: AlpinetrekMountain Equipment £350 In stock. Free delivery. Regular left zip in stock; Regular right zip out of stock.
View at shop: Mountain EquipmentPrices checked 8 Nov 2026 on each shop's own page; shops can change them. We earn no commission on these links; shops are listed by price. More
Our ratings (out of 10)
1 to 10, compared with the whole market. Each says what it's based on. How we score
Warmth
From maker's figures 9/10How cold a night you can sleep comfortably through. 9: Among the best you can buy for this.
Mountain Equipment's page labels its ratings 'EN13537/ISO23537': comfort -5 °C, limit -11 °C. Comfort -5 °C is in the -5 °C or colder band. The maker's figure, not re-tested by us. Its own 'Good Night's Sleep' figure of -10 °C is not used.
Room inside
Estimate: only 1 review about room inside (fewer than the 3 we need, so never above 8) 4/10How much room to move, bend your knees and sleep on your side. Roomier is comfier. 4: A bit below average.
Packstack finds the Alpine 2.0 fit snug and points broad-shouldered sleepers to the wider GT 600; it cites owners also calling it narrow.
Weight
From maker's figures 6/10How much it adds to your pack. 6: A bit better than average.
1,030 g for the Regular (stuff sack and storage bag not included) sits in the 1,000-1,299 g band.
Packed size
From maker's figures 3/10How much room it takes in your rucksack. 3: Below average. Fine for some trips, not others.
The maker gives no litres, only a packed size of 25 x 23 x 20 cm. As a box that is 25 x 23 x 20 = 11,500 cm3, so 11.5 L, in the 9-12.9 L band. The box is the outer limit of a soft sack, so the real figure may be a little lower, but it would need to be under 9 L to change band.
In short
Good for
- Cold spring, autumn and early-winter camps in the UK hills, down to about -5 °C comfort
- Backpackers who want a warm down bag at about 1 kg
Strengths
- Comfort -5 °C and limit -11 °C for 1,030 g, which is a strong warmth-for-weight figure
- 620 g of 700+ fill power duck down, with slanted box-wall baffles and a shaped 5-baffle hood
- Full-length zip baffle (Gemini) and a magnetic collar closure
- Supplied with a roll-top waterproof stuff sack and a storage cube
- Down is traceable through a DOWN CODEX code in each bag
Weaknesses
- 700 fill power is a middle grade, and the packed size of about 11.5 L is not small for a bag of this weight
- Tapered Alpine fit; the maker sells a roomier Helium GT version for people who find it tight
- Down is not water-repellent, so it loses warmth if it stays wet; a synthetic bag is safer for persistently wet trips
- No independent tests of the current bag found, so damp performance, comfort and durability are estimates, not reviewed scores
- Ratings are shown as 'EN13537/ISO23537' on the maker's page, and its own -10 °C 'Good Night's Sleep' figure is warmer than the standard comfort figure
Sources
We haven't tested this ourselves. Every score comes from these specs, tests and reviews.