Rab
Rab Neutrino Down Sleeping Bag (-6°C), 2026 model
Where it fits
- Also works for
- Backpacking and wild camping
- Not for
- Winter mountain
Why these labels
- Backpacking and wild camping: Light to carry: 0.9 kg
- Winter mountain: Comfort rating 0 °C: too cold for winter nights
From the maker's stated use and the published specs.
- Summer wild camp: 6/10 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: 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: 7/10 How much it adds to your pack, compared with the whole market.
Comfort 0 °C, limit -6 °C (ISO 23537).
No shop we checked has it in stock
Spring-to-autumn hill camps in the UK, including nights that dip to light frost
- Comfort
- 0 °C
- Limit
- -6 °C
- Fill
- 800 fill down
- Weight
- 870 g (Regular)
Packed size 7.6 L, 30 cm long and 18 cm across Compare with a 2-litre bottle
About as long as a 2-litre bottle and about one and a half times as wide. Drawn to scale.
Where to buy
Alpinetrek £385.36 Out of stock. Regular out of stock; only the Long is in stock.
View at shop: AlpinetrekRab £470 Out of stock.
View at shop: RabPrices 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 ISO 23537 comfort 0 °C (limit -6 °C) sits in the -4.9 to 0 °C band: good for spring and autumn with light frost, not a winter bag.
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.
Reviewers describe the Neutrino as a narrow, tapered mummy: snug and efficient, fine if you sleep fairly still, but restrictive for side sleepers or restless sleepers. Rab sells a Wide version for more room.
Weight
From maker's figures 7/10How much it adds to your pack. 7: Better than most.
870 g (Regular) sits in the 700–999 g band.
Packed size
From maker's figures 5/10How much room it takes in your rucksack. 5: Does the job. Average for wild-camping gear.
Maker gives only two figures, 30 x 18 cm, so it's a stuff sack: 3.1416 x 9 x 9 x 30 = 7,634 cm³, so 7.6 L, in the 6–8.9 L 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*
Estimate: only 1 review about comfort to sleep in (fewer than the 3 we need, so never above 8) 8/10How comfy the shape, hood and fabric feel; not the temperature rating.
1 review on comfort to sleep in, e.g. "materials that feel high quality throughout".
Zip*
Estimate: only 2 reviews about zip (fewer than the 3 we need, so never above 8) 8/10How smoothly the zip runs without snagging.
2 reviews on zip, e.g. "The YKK anti-snag zip works as intended".
In short
Good for
- Spring-to-autumn hill camps in the UK, including nights that dip to light frost
- Backpackers who want a warm down bag that packs small and weighs under 1 kg
Strengths
- Good warmth for its weight, with the maker's comfort rating at 0 °C
- Packs to about the size of a small loaf
- Down is treated to cope better with damp, and one reviewer found it kept its loft after getting damp
- Zip is anti-snag and works both ways, so you can vent from the foot end
Weaknesses
- A close, tapered fit: people who sleep on their side or move a lot may find it snug (a Wide version is sold)
- Not a true winter bag: reviewers rate it as three-season with light frost, and the comfort figure is 0 °C
- Down loses warmth if it stays soaked, so a synthetic bag is safer for persistently wet trips
- Only three independent reviews of this 2026 version so far, so some scores are 'Not enough evidence'
Sources
We haven't tested this ourselves. Every score comes from these specs, tests and reviews.
ShowHide sources (5)
- Rab: Neutrino Down Sleeping Bag (-6°C) product page (ISO 23537-1:2022 rating, weight, packed size)
- Outdoors Magic: Rab Neutrino -6 Sleeping Bag review
- Men's Journal (via Yahoo): I Tested Rab's New Neutrino Sleeping Bag (Neutrino 20, the US name for this bag)
- Mountain Life: ML Tested, Rab Neutrino Down Sleeping Bag (-6°C)
- Mountain Life: ML Tested, Rab Neutrino Down Sleeping Bag (-6C)