An ultra-thick, four-season insulated sleeping mat engineered for cold-climate adventures, combining high-loop Air Sprung Cell comfort with an extreme R-Value for maximum thermal protection.
The Sea to Summit Ether Light XT Extreme is the warmest mat in the Ether Light family, specifically designed for winter alpine treks and high-altitude camping. Utilising a unique Air Sprung Cell construction with extra-large loops, this mat provides a stable 10cm thickness that prevents "bottoming out" even for side sleepers. The internal insulation features dual-density layers of Thermolite, which trap radiant heat and prevent convective heat loss to the frozen ground. Despite its heavy-duty thermal rating of R 6.2, the mat remains remarkably lightweight and packable, making it the premier choice for Australian adventurers heading to the Snowy Mountains or the Tasmanian wilderness in mid-winter.
Key Technical Features
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ASTM R-Value of 6.2: Provides extreme insulation, making it suitable for use on snow and frozen ground in temperatures well below freezing.
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10cm Air Sprung Cell Technology: The high-loop design creates larger air pockets that contour to your body shape, providing a more "homelike" mattress feel than traditional longitudinal baffles.
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Thermolite Insulation: Dual layers of high-loft synthetic insulation fill the Air Sprung Cells to prevent air movement and maximize heat retention.
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30D/40D Nylon Face Fabric: Constructed with a durable, quiet, and grip-treated nylon shell that prevents the "slippery" feel common with other ultralight mats.
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Pillow Lock System: Features hook-and-loop patches that secure a Sea to Summit Aeros pillow to the mat, ensuring it stays in place throughout the night.
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Airstream Pump Integration: The storage stuff sack doubles as a high-volume pump bag, allowing for rapid inflation with minimal effort and reducing moisture build-up inside the mat.
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Antimicrobial Treatment: The internal TPU lining is treated with an Ultra-Fresh antimicrobial formula to prevent mould and fungal growth caused by warm, moist air.
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Field Repair Kit Included: Typically supplied with 3M adhesive patches to ensure you can manage punctures even in remote backcountry locations.
Technical Specifications
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R-Value: 6.2 (Tested to ASTM F3340-18 standards).
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Thickness: 10cm.
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Weight: Approx. 720g (Regular) / 950g (Large).
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Dimensions (Regular): 183cm x 55cm.
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Material: 30D/40D high-tenacity grip-skin nylon with TPU lamination.
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Shape: Available in Tapered (Mummy) and Rectangular profiles.
Best For
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Four-Season Camping: Essential for any trip where temperatures are expected to drop below 0°C.
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Side Sleepers: The 10cm depth allows hips and shoulders to sink in without hitting the ground, providing superior pressure point relief.
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Alpine Expeditions: Ideal for mountaineering and winter bushwalking where weight must be balanced against critical thermal safety.
