Sea to Summit Etherlight XT Extreme Insulated Air Sleeping Mat

Sea to Summit have taken their best-selling EtherLightXT mat and increased the insulation to make it warmer for when the mercury drops. With an R-value over 6, the 10 cm thick EtherLightXT Extreme air mat redefines lightweight sleeping comfort for winter adventures around the globe. Sea to Summit's Air Sprung Cells are the reason you will sleep better on the air mats. Each Air Sprung Cell deforms independently and allows the mat to conform to your body shape. This provides support and comfort by more evenly dispersing pressure across the mat’s surface.

For the extra thick (XT) EtherLight design, STS use many TPU loops to connect the top and bottom fabric layers to the Air Sprung Cell dot weld pattern. These loops allow the top and bottom layers to be positioned further apart which creates larger pockets of air when inflated—perfect for side sleepers. This design also requires less fabric overall which means great stability and comfort for less weight. Dual-density layers of THERMOLITE® insulation fill the Air Sprung Cells and work together to prevent convective heat transfer and boost warmth while remaining lightweight and packable. When the mercury drops, the EtherLightXT Extreme’s 6.2 (women’s 6.3) ASTM R-value will keep you cushioned and insulated from the cold hard lumps and bumps beneath.


  • Includes an Airstream Pump that is integrated into the stuff sack for quick and easy inflation
  • Extra Thick (XT) loop baffle Air Sprung Cells - Air Sprung Cells are the core technology of our sleeping mat range, and are the reason why you will sleep better on a Sea to Summit sleeping mat. Instead of the typical baffled construction, Sea to Summit sleeping mats are constructed using a dot-weld pattern to create a high surface-area matrix of interconnected chambers called Air Sprung Cells. Air Sprung Cells operate in the same way as a pocket spring mattress. As each cell deforms independently the mattress conforms to your body shape. This makes for a softer and more comfortable feel with more body contact area and even dispersion of pressure.
  • Lightweight, quiet and grippy 30/40D Nylon fabric, field repairable with included self-adhesive patches
  • Ultra-Fresh anti-microbial treatment to the TPU formula to prevent internal mould growth
  • PillowLock attaches your Aeros pillow to your mat, holding it in place for a slip-free sleep
  • Thermal Insulation Technology - Exkin Platinum is a very lightweight, quiet non-woven fabric that has a thin metalized layer applied to the surface. Exkin Platinum thermal technology reflects radiant heat loss back to the user.
  • Thermolite insulation, designed for ultimate performance, is made from specially engineered fibers to achieve a high CLO value with low weight. Thermolite HL-1 high loft insulation is a fiberfill constructed with a unique 3D crimp of hollow-core and solid fibers, which provide excellent lightweight warmth with superior durability. The Thermolite insulation lofts up inside the Air Sprung Cells to prevent convective heat loss from your warm body to the cold ground.
  • Exkin Platinum and Thermolite are combined to great effect in each of the insulated versions of our mats.
  • Multi-Function Valve - To make inflation and deflation easier Sea to Summit has developed the multi-function valve. Our valve integrates an inflate port with a one-way valve to prevent air loss before you seal the valve, a rapid air dump deflate port, and a fine-tune button to adjust for comfort - all in one compact, low profile unit.
  • Inflate and deflate pull tabs are tactile and colour coded for easy identification.
    • 30/40D Nylon Fabric - STS developed the 40D ripstop nylon face fabric to hit the right balance between weight and durability. On the inside they apply a bright white TPU to make the fabric airtight and weldable. On the outside they apply a thin proprietary coating to reduce the slipperiness of the surface, increase puncture with self-adhesive patches.
    • Stuff Sacks and Repair Kits - All Sea to Summit sleeping mats come with a quality stuff sack sized to suit your mat. We also include a small repair kit containing six self adhesive patches for repairing punctures in the field, and a spare silicone one-way valve flap.
Primary Material:
Thermolite Fabric
Weight Kg:
Reg - 0.72 kg / Large - 0.95 kg
Reg - 183 cm / Large - 198 cm
Reg - 55 cm / Large - 64 cm
10 cm
Regular, Large (L)
Sleeping Mat Rolled Size:
Reg - 17.5 x 24 cm / Large - 18.5 x 28 cm


Collections: Sea to Summit, Sleeping, Sleeping Mats

Related Items