Mountain Equipment
Mountain Equipment Helium 250 Down Sleeping Bag
Best use
- Made for
- Backpacking and wild camping
- Also works for
- Bikepacking
- Not for
- Winter mountain
Why these labels
- Backpacking and wild camping: The maker states this use, and the published specs do not rule it out.
- Bikepacking: Small enough for bike bags: packs to 4.8 litres
- Winter mountain: Comfort rating 7 °C: too cold for winter nights
From the maker's stated use and the published specs.
- Summer wild camp: 7/10 UK, roughly May to September, nights above about 8 °C, sheltered pitches.
- Three-season hills: 4/10 UK hills in spring and autumn. Wind, rain, and nights near freezing. Capped at 4: needs warmth 7+ (comfort 0 °C or colder).
- Winter camp: 4/10 UK winter or high ground. Below freezing, strong wind, possibly snow. Capped at 4: needs warmth 9+ (comfort -5 °C or colder).
- Weight: 9/10 How much it adds to your pack, compared with the whole market.
Comfort 7 °C, limit 2 °C (EN 13537).
Lowest price we found
£209.99 at Ultralight Outdoor Gear
Go to Ultralight Outdoor Gear Compare 3 shopsSummer wild camps in the UK where nights stay above about 7 °C
- Zip side
- Both
- Comfort
- 7 °C
- Limit
- 2 °C
- Fill
- 700 fill down
- Weight
- 660 g (Regular)
Packed size 4.8 L, 19 x 17 x 15 cm Compare with a 2-litre bottle
Shorter than a 2-litre bottle and about one and a half times as wide. Drawn to scale.
Where to buy
Ultralight Outdoor Gear £209.99 In stock. Free delivery.
View at shop: Ultralight Outdoor GearMountain Equipment £250 In stock. Free delivery.
View at shop: Mountain EquipmentAlpinetrek £257.95 In stock. Free delivery.
View at shop: AlpinetrekPrices 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 4/10How cold a night you can sleep comfortably through. 4: A bit below average.
Maker's comfort 7 °C (limit 2 °C; its page labels the test EN13537/ISO23537) sits in the 5.1 to 10 °C band: a summer bag. The maker's own 'Good Night's Sleep' figure is 1 °C.
Room inside
Estimate: only 1 review about room inside (fewer than the 3 we need, so never above 8) 6/10How much room to move, bend your knees and sleep on your side. Roomier is comfier. 6: A bit better than average.
One group test calls the fit neat but not tight. Maker uses a tapered Alpine fit; a wider GT version exists for more room.
Weight
From maker's figures 9/10How much it adds to your pack. 9: Among the best you can buy for this.
660 g (Regular) is under 700 g. A UK shop lists 706 g; we band the maker's figure.
Packed size
From maker's figures 8/10How much room it takes in your rucksack. 8: Clearly better than most.
Maker gives 19 x 17 x 15 cm: 19 x 17 x 15 = 4,845 cm³, so 4.8 L, in the 4–5.9 L band.
In short
Good for
- Summer wild camps in the UK where nights stay above about 7 °C
- Backpackers and cycle tourers who want a very small, light down bag
Strengths
- 660 g and about 4.8 L packed, with 261 g of 700 fill power duck down
- Slanted box-wall baffles, 5-baffle hood and a full-length zip baffle
- Waterproof roll-top stuff sack included
- Shell and lining are 20D recycled nylon with a PFAS-free DWR finish
- The one independent test we found of the current bag (Trek and Mountain, 2023) praised its hood, zip and fabrics
Weaknesses
- Comfort rating is 7 °C: a summer bag, not for spring or autumn frost
- Slim Alpine Fit: broad or restless sleepers may find it snug
- Duck down at 700 fill power, with no stated water-repellent treatment on the down
- Only one independent review of the current version, so damp, comfort and durability scores are Not enough evidence
Sources
We haven't tested this ourselves. Every score comes from these specs, tests and reviews.