Sea to Summit Altitude AtI - Women's Long

Designed for above-treeline conditions where thermal performance and moisture resistance are non-negotiable.

The Sea to Summit Altitude AtI Women's Long is a down sleeping bag engineered for extreme cold-weather use. The women's-specific tapered rectangular shape offers more interior volume than a standard mummy bag without sacrificing heat retention. RDS-certified 750+ Loft ULTRA-DRY Down maintains insulation performance in damp conditions, making it suitable for high-altitude and shoulder-season environments.

Features

• Women's-specific tapered rectangular shape for increased interior space and adaptable warmth

• RDS-certified 750+ Loft ULTRA-DRY Down fill for reliable insulation in wet conditions

• Free-Flow half left-side zip, full-length 2-way YKK #5 right-side zip, and separate foot zip for ventilation and quilt conversion

• Zip coupling system — pairs with a compatible bag

• Large internal security pocket

• Includes Ultra-Sil compression bag and storage cell

Technical Specifications

• Shell: 20D Nylon (super-light)

• Fill: RDS 750+ Loft ULTRA-DRY Down

• Temperature rating: Comfort -4°C / Limit -10°C / Extreme -29°C

• Body length: 183 cm

• Packed size: ø18 × 40 cm

• Weight: 1.17 kg