Mountain Equipment
Mountain Equipment Xenith III (Regular)
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 -2 °C: too cold for winter nights
From the maker's stated use and the published specs.
- Summer wild camp: 8/10 UK, roughly May to September, nights above about 8 °C, sheltered pitches.
- Three-season hills: 7/10 UK hills in spring and autumn. Wind, rain, and nights near freezing.
- 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 -2 °C, limit -8 °C (ISO 23537).
No shop we checked has it in stock
Spring and autumn nights in the UK hills when you want a warm bag that is very light
- Zip side
- Left
- Comfort
- -2 °C
- Limit
- -8 °C
- Fill
- 900 fill down
- Weight
- 690 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
Mountain Equipment £550 Out of stock.
View at shop: Mountain EquipmentUltralight Outdoor Gear £469.99 Out of stock.
View at shop: Ultralight Outdoor GearPrices 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 7/10How cold a night you can sleep comfortably through. 7: Better than most.
Maker's comfort figure of -2 °C sits in the -4.9 to 0 °C band. The maker names EN 13537/ISO 23537 ratings but not which edition; one review calls it conservative in real use.
Room inside
From reviews 6/10How much room to move, bend your knees and sleep on your side. Roomier is comfier. 6: A bit better than average.
A close-fitting alpine mummy that reviewers find comfortable and not restrictive, but not spacious: fine for most, less so for broad sleepers or those who want to move around a lot.
Weight
From maker's figures 9/10How much it adds to your pack. 9: Among the best you can buy for this.
The maker's 690 g for the Regular is under 700 g. One UK shop lists 701 g; that would be the 4 band, but we use the maker's figure.
Packed size
From maker's figures 8/10How much room it takes in your rucksack. 8: Clearly better than most.
A UK shop lists 19 x 17 x 15 cm (maker gives no packed size): 19 x 17 x 15 = 4,845 cm³, so 4.8 L, in the 4–5.9 L band. A review's 25 x 16 cm roll-top size works out at 5.0 L, same band.
What reviewers say (out of 10)
Ratings marked * are from reviews and are not part of the trip score. They are reviewers' scores, not our own measurements. How we score
Comfort to sleep in*
Reviewers' average 8/10How comfy the shape, hood and fabric feel; not the temperature rating.
5 reviews on comfort to sleep in, e.g. "the Mountain Equipment Xenith III sleeping bag is surprisingly comfortable".
Zip*
Reviewers' average 7/10How smoothly the zip runs without snagging.
4 reviews on zip, e.g. "The bag also has an excellent two-way YKK zipper on the left side".
In short
Good for
- Spring and autumn nights in the UK hills when you want a warm bag that is very light
- Backpackers and mountaineers who count every gram and can afford it
- Cold sleepers who want a full-length zip and a proper hood and collar
Strengths
- One of the warmest bags around for its weight: comfort -2 °C for 690 g
- Packs small, around 5 litres in its own roll-top sack
- Full-length zip, shaped hood and draught collar, which many ultralight bags skip
- One reviewer found the -2 °C comfort rating conservative, sleeping warm on snow well below it
Weaknesses
- The down isn't treated to resist water, so a wet bag loses warmth; keep it in a dry bag
- The very thin 10D shell isn't tough: one reviewer advises carrying repair tape
- Too warm for most UK summer nights, and the maker's -7 °C 'Good Night's Sleep' figure is its own, not the lab rating
- Fairly snug, and the side zip is fiddly with cold hands for one reviewer
Sources
We haven't tested this ourselves. Every score comes from these specs, tests and reviews.
ShowHide sources (9)
- Mountain Equipment: Xenith III sleeping bag
- Ultralight Outdoor Gear: Xenith III spec table (shop; packed size)
- Live for the Outdoors: Mountain Equipment Xenith III review
- UKHillwalking: Xenith III Sleeping Bag, a 12-month review by Tom Ripley
- Trek & Mountain: First Look, Mountain Equipment Xenith III
- Mountainreview: Mountain Equipment Xenith III review
- UKC: Mountain Equipment Xenith III review (12-month test)
- Eddy's Adventure: My practical test of the Mountain Equipment Xenith III
- UKHillwalking (same review on UKC): Xenith III Sleeping Bag, a 12-month review