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A warm, reliable down sleeping bag designed for extended three-season and colder conditions
Rab says:
Warm, robust, and reliable down-filled sleeping bag for regular mountain use. Built to prioritise comfort with a wide mummy shape, roomy footbox, and sidewall baffles, it's perfect for trekking and backpacking adventures.
Our Verdict
The Women's Ascent -12C uses 650-fill-power duck down with a substantial 680g fill to deliver dependable insulation, weighing 1389g. This higher fill weight prioritises consistent warmth over minimum weight, providing a stable warmth-to-weight ratio for colder conditions from early spring through to late autumn, with the ability to push towards winter use. The comfort limit of around -12°C feels realistic when paired with an appropriate mat.
The women’s specific fit is shaped to improve thermal efficiency while maintaining comfort, sitting within the same wide mummy shape. This still offers noticeably more space than most performance-focused bags, allowing easier movement in the bag at night. The L.O.F.T construction uses alternating baffle sizes to distribute down more efficiently, helping maintain warmth without adding excess weight. Sidewall baffles keep the insulation positioned around the body, reducing cold spots. A 3/4-length two-way zip and an additional arm zip help to vent heat and tailor the level of insulation.
The Pertex Quantum fabric balances weight and durability, and the overall construction feels robust for a bag in this category. Features such as the insulated collar, shaped hood and internal pocket add to the practical feel in colder conditions. Overall, this is a well-balanced option for those prioritising comfort and reliability over outright weight savings in a more capable cold-weather sleep system.
- Reviewed by Ultralight Outdoor Gear
Features
- L.O.F.T™ baffle technology reduces down migration, optimising heat retention and pack size
- Sidewall baffle construction for increased down loft and greater side sleeping comfort
- Anatomically fitted hood with drawcord adjustment to maximise comfort and heat retention
- Internal cordlocks positioned below the collar bone for greater side sleeping comfort
- YKK® zipped internal stash pocket
- 3D shaped neck collar with recycled Stratus™ insulation
- 2-way YKK® 3/4 length main zip with synthetic-filled baffle
- YKK® anti-snag zip insert and anti-snag internal zip guard
- Anatomically shaped foot box for relaxed sleeping posture
- Drawcord stuff sack included
- Zipped storage sack with water-resistant base for home storage
- Hand-filled in Derbyshire UK
- Wide mummy shape
- YKK® zipped arm access vent with integrated snap closure to retain heat during tent-based tasks
- Temperature rated in accordance with ISO 23537-2:2022
Specifications
Temperature Rating
- Comfort: -5°C
- Comfort Limit: -12°C
- Extreme: -33°C
Regular
- Weight: 1389g
- Lenth: 200cm
- Width: 80cm
Long
- Weight: 1428g
- Lenth: 215cm
- Width: 80cm
Material & Construction
- 20D Pertex® Quantum nylon ripstop (38g/m²) with fluorocarbon-free DWR
- Lining: Recycled 20D nylon, 38g/m²
- 650FP European duck down with Grangers fluorocarbon-free hydrophobic finish (680g / 24.0oz)
- 100% Woven Polyamide Shell , Down filled sleeping bag
