Rab
Rab Ascent Down Sleeping Bag (0°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 5 °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: 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: 7/10 How much it adds to your pack, compared with the whole market.
Comfort 5 °C, limit 0 °C (ISO 23537).
Summer camps and spring or autumn bothy trips in the UK where nights stay above about 5 °C
- Zip
- Half
- Comfort
- 5 °C
- Limit
- 0 °C
- Fill
- 650 fill down
- Weight
- 940 g (Regular)
Packed size 11 L, 35 cm long and 20 cm across Compare with a 2-litre bottle
A bit longer than a 2-litre bottle and about twice as wide. Drawn to scale.
Where to buy
Alpinetrek £224.96 In stock. Free delivery. Regular, left zip in stock; right zip out of stock.
View at shop: AlpinetrekUltralight Outdoor Gear £254.99 In stock. Free delivery.
View at shop: Ultralight Outdoor GearRab £300 In stock. Free delivery.
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 5/10How cold a night you can sleep comfortably through. 5: Does the job. Average for wild-camping gear.
Maker's ISO 23537 comfort 5 °C (limit 0 °C) sits in the 0.1 to 5 °C band: a spring-to-autumn bag, not for frost.
Room inside
Estimate from maker's specs: maker's shoulder girth (fewer than 3 reviews about room) 8/10How much room to move, bend your knees and sleep on your side. Roomier is comfier. 8: Clearly better than most.
No review we found says how roomy it is, so this is an estimate from the maker's shoulder girth.
Weight
From maker's figures 7/10How much it adds to your pack. 7: Better than most.
940 g (Regular) sits in the 700–999 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.
Maker gives only two figures, 20 x 35 cm, so it's a stuff sack (smaller figure as the diameter): 3.1416 x 10 x 10 x 35 = 10,996 cm³, so 11.0 L, in the 9–12.9 L band.
In short
Good for
- Summer camps and spring or autumn bothy trips in the UK where nights stay above about 5 °C
- Side sleepers and restless sleepers who want a roomy cut and a wide foot box
Strengths
- Wide mummy cut with sidewall baffles and a roomy foot box, built for comfort
- Down is treated to resist damp (Grangers hydrophobic finish)
- Two-way 3/4-length zip plus a separate arm vent zip, so you can cook or use a phone without opening the whole bag
Weaknesses
- Comfort rating is 5 °C: cold sleepers will want layers or a warmer bag near freezing
- 650 fill power duck down makes it heavier and bulkier than the Neutrino 0C for the same limit rating: 940 g and 11 L packed against 700 g and 6 L
- No independent hands-on reviews of this 2026 bag yet, so damp, comfort and durability scores are Not enough evidence
- The 3/4-length zip limits venting from the foot end compared with a full-length zip
Sources
We haven't tested this ourselves. Every score comes from these specs, tests and reviews.