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Sea to Summit Ascent AC II - Regular

Size: Regular

The Sea to Summit Ascent II is a unisex down sleeping bag that is light, warm, and comfortable, and designed to be surprisingly versatile for all adventures. 

Boasting a comfort limit of -10*c, the Sea to Summit Ascent II offers a balance of comfort vs weight and is a tapered rectangular shape, which allows more room to spread out compared to a traditional mummy style bag. The Free-Flow triple-zip design ensures your sleeping bag retains maximum warmth and efficiency when needed and provides multiple ventilation options when it’s not. The half zip on the right side of the bag provides freedom of movement for both arms, additional ventilation and means the top third of the bag can be folded down as a mini quilt. The full length, two-way left side zip and separate foot zip transforms the bag into a full quilt for when the mercury climbs higher than expected.

If it’s warmth you’re after, close all the zips, pull the cord locks tight to drag everything in, and relax in luxurious comfort. The generous allocation of high quality 750+ Loft Ultra-Dry treated down ensures great insulation, while the oversized draft tubes prevents your body heat escaping. The panelled footbox and 3-dimensional hood make sure you’re not compressing the down when you’re trying to stay warm. Vertical baffles over the chest section ensure the down insulation cannot migrate or shift to the outside of the bag during sleep, creating cold spots. A side block baffle construction maintains the 60/40 fill ratio, keeping more down on the top of the bag for maximum insulation.

More Help? For further assistance on choosing your down sleeping bag, we have an article explaining fill power, the pros and cons of down over synthetic insulation and more info on caring for your bag available to view here: A Guide to Down Sleeping Bags.


  • Tapered rectangular shape for perfect balance of space and adaptable warmth
  • Super-light 20D Nylon shell and lining fabrics for minimal packed size and maximum breathability
  • RDS 750+ Loft ULTRA-DRY Down™ for superior insulating power
  • Vertical chest baffles prevent down migration and cold spots
  • Free-Flow half right side, full length two-way #5 YKK left side and separate foot zips for freedom of movement, increased ventilation and dual-use as a quilt
  • Oversized draft tube with anti-snag materials, prevents heat loss through zipper
  • Oversized neck draft tube with a dual adjustment system for even cinching and maximum warmth
  • Generously sized hood and dual cord adjustment for maximum warmth retention
  • Anatomically shaped footbox allows maximum down lofting, minimising heat loss from your feet
  • Large internal pocket for GPS / phone / valuables
  • Includes Ultra-Sil™ Compression Bag for compact storage
  • Zip Coupling: This bag can be zipped to the Sea to Summit Women’s Altitude, Journey and Venture sleeping bags


  • Maximum body size: 183 cm
  • Inner bag length: 194 cm
  • Comfort Temperature: -4 °C
  • Comfort Temperature limit: -10 °C
  • Extreme temperature limit: -29 °C
  • Maximum inner width: 70 cm 
  • Insulated collar: Yes
  • Main Fabric: 20D Nylon
  • Filling: 550g of ULTRA-DRY treated down
  • Fill power 750 cuin

Weight: 1110g

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