The Ether Light XT Extreme is extra thick and exceptionally warm, providing true four-season performance. The XT Air Sprung Cells offer four inches of stability and comfort, while dual-density layers of THERMOLITE® insulation prevent convective heat loss and internal air movement. Features: - 6.2 R-Value for cold weather adventures. - Four inches thick Ether Light XT Air Sprung Cells for a plush sleeping experience. - Dual-density Thermolite® insulation filling the inner space to prevent heat loss. - Lighter, quieter, and durable 30D/40D face fabric with Sea to Summit’s liquid-extruded lamination for reliability. - Multi-function valve and Airstream Pump/stuff sack for easy inflation, deflation, and adjustment. - Anti-microbial treatment on the TPU lamination to prevent internal mold growth. - PillowLock system to secure Sea to Summit Aeros Pillow. - Includes a stuff sack (doubles as a pump), a repair kit with six self-adhesive patches, and a spare valve insert. Tech Specs: - Best Use: Cold Weather Backpacking - Comes With: Stuff sack w/ integrated pump, repair kit & Pillow Lock - Fabric: Durable 30D/40D nylon - R-Value: 6.2 - Season Rating: 4 Season - Special: Anti-microbial liquid-extruded TPU lamination to reduce delamination - Thickness: 4 in / 10 cm PERFORMANCE: 4 Season PACKED SIZE: 7.3 x 11in 18.5 x 28cm Dimensions: 183x64cm