The Rab Women's Ascent Down Sleeping Bag at -18°C is the most versatile sleeping bag in the Ascent range — the right choice for serious three-season and cold-winter trekking where expedition-rated conditions are not the primary objective. Rated to -10°C comfort and -18°C limit of comfort under ISO 23537-1:2022, it carries 880g of 650FP European duck down in the same women's-specific wide mummy construction, L.O.F.T™ baffle system, and Pertex® Quantum shell as the -24°C version, at 240g less weight and a wider temperature versatility window for year-round mountain use. Hand-filled in Derbyshire.

• ISO-rated to -10°C comfort, -18°C limit — the -10°C comfort rating means a relaxed woman can sleep through a standard night at this temperature without feeling cold. The -18°C limit of comfort is the survival threshold rather than a practical sleeping temperature. For most mountain trekking in Ireland, Scotland, the Alps in summer and shoulder seasons, and Himalayan trekking routes at altitude, this is the correct specification.
• 880g of 650FP European duck down — treated with Grangers fluorocarbon-free hydrophobic finish for moisture resistance without PFAS chemistry. 200g less fill than the -24°C version, which accounts directly for the 240g weight saving and the wider comfort range making it usable across more conditions without running too warm.
• L.O.F.T™ baffle construction — alternating wide and narrow baffles distribute the down precisely for maximum warmth-for-weight. The same proprietary construction used across the full Ascent range.
• Sidewall baffles for side sleepers — vertical baffles prevent down migration away from the bag's flanks when you roll onto your side, eliminating the cold spots at the seams that plague conventional mummy bags for side sleepers.
• Women's wide mummy fit — specific to female anatomy, with broader shoulder and hip girth and a roomy anatomically shaped footbox. Sized to wear over base layers and a midlayer in cold conditions without constriction.
• Synthetic-insulated collar and cinchable hood — the collar uses synthetic fill for moisture resistance at the highest-condensation zone on the bag. The hood seals fully around the face in cold conditions.
• Two-way YKK® ¾ length main zip with second access zip — the secondary shorter zip with snap closure allows arm access for cooking or adjusting layers without releasing heat from the lower bag. Full anti-snag insert and internal zip guard throughout.
• Internal cordlocks positioned below the collar bone — accessible while lying on your side without shoulder or ear pressure from a standard top-mounted position.
• 20D Pertex® Quantum shell, 100% recycled fabrics, PFAS-free throughout — outer, second outer, and liner all use 100% recycled materials. 30% recycled content across the total product. No PFAS in any component.
• Hand-filled in Derbyshire, UK — never compressed before filling, preserving full down loft from the first use.
• Zipped internal stash pocket, drawcord stuff sack, and zipped storage sack — storage sack has a water-resistant base for home storage without compressing the down long-term.

To extend the temperature range of this bag for colder conditions, a Sleeping Bag Liner adds a meaningful warmth increment without changing the bag itself.  Browse the full Rab range.