Sea to Summit Ether Light XT Extreme Sleeping Mat - Rectangular Large

ASTM R-Value: 6.2 / Dimensions: 201 x 64 x 10cm / Packed Size: 18.5 x 28cm
Weighs 1072g (excluding stuff sack)
Code: SS21330
  • £217.99
  • (FREE Delivery on orders over £15)
  • RRP £234.99
Item out of Stock | Usually dispatched within 24 hours

Building on the success of the original Ether Light XT comes this Extreme version. With double the amount of insulation and an R-Value almost twice as high this mat will certainly keep you insulated from the cold in winter. 

Sea to Summit says:

We’ve taken our best-selling Ether Light XT mat and increased the insulation to make it warmer for when the mercury drops. With an R-value over 6, our 10cm thick Ether Light XT 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 our 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 our extra thick (XT) Ether Light design, we use many TPU loops to connect the top and bottom fabric layers to our 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.

Sea to Summit's Ether Light XT Extreme Sleeping Mat impresses straight out of the box. It was straightforward to inflate with the the well thought out integrated stuff and pump sack. The 10cm depth of the mat sets it apart from its competitors providing extra comfort and keeping you further away from the cold ground whichever way you sleep. The outer fabric is tough and grippy so the mat will stay where you want it.

In order to boost the insulation and R-Value on the original Ether Light series there is a dual layer of the Thermolite insulation which has a massive effect on the temperatures it can be used in. This increase in insulation does mean that the weight and pack size have increased quite significantly. However,if you are going to be using this mat in winter then the weight and pack size are worth the penalty for the level of insulation and comfort that this mat provides.

- Reviewed by Ultralight Outdoor Gear

Help and advice:
  • ASTM R-value 6.2 is designed for cold-weather use
  • Dual-density layers of THERMOLITE® insulation
  • Extra thick (XT) Air Sprung Cell construction for 10cm stable comfort 
  • Lightweight, quiet and grippy 30/40D Nylon face fabric
  • Field repairable with included self-adhesive patches 
  • Ultra-Fresh® anti-microbial treatment added to the TPU formula prevents internal mould growth 
  • Pillow Lock™ attaches an Aeros™ pillow to mat
  • Quick and easy inflation, deflation and adjustment with the multi-function, high flow-rate valve and supplied Airstream™ Pump Sack
  • Weighs: 1072g (excludes bag/pumpsack)
  • Airstream pumpsack/storage bag weighs: 62g
  • Dimensions: 201 x 64 x 10cm
  • Packed Size: 17.5 x 24cm
  • ASTM R-Value: 6.2

ASTM R-Value: From 2020, there is a new industry standard for measuring the R-value (level of insulation) of sleeping mats – ASTM F3340-18. This new standard is the sleeping mat equivalent to the EN rating for sleeping bags.

You can now directly compare the R-value of mats rated using the ASTM F3340-18 with confidence that is a fair and accurate comparison between mats. In simple terms, the higher the R-value, the warmer the mat.

In general terms, an R-value below 2.0 is for summer use, 2.0 to 4.0 is for cooler 3 season use and 4.0+ is for winter temperatures. This will be also be dependent on your sleeping bag, how cold you sleep etc. Please contact our customer service team if you need advice on choosing the right mat for your activity.

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