Sea to Summit Ether Light XR Insulated vs Exped Ultra 6.5R
In short: The Sea to Summit Ether Light XR Insulated costs $1 less; the Exped Ultra 6.5R is warmer by 2.8 points of R-value; the Exped Ultra 6.5R saves 1.1 oz; the Sea to Summit Ether Light XR Insulated is 4 inches thick against 3.5.
| Spec | Sea to Summit Ether Light XR Insulated | Exped Ultra 6.5R |
|---|---|---|
| Approx. price | ~$199 | ~$200 |
| R-value | R 4.1 | R 6.9 |
| Season band | Cold three-season | Winter |
| R-value standard | ASTM F3340 | ASTM F3340 |
| Weight | 1 lb 0.6 oz | 15.5 oz |
| R per ounce | 0.25 R/oz | 0.45 R/oz |
| Thickness | 4 in | 3.5 in |
| Pad type | air | air |
| Inflation | pump sack | pump sack |
| Dimensions | 72 × 22 in | 72 × 20.5 in |
| Packed size | 8 × 4 in | 9.1 × 4.3 in |
| Insulation | ThermalCore multi-layer polyethylene film inside Air Sprung Cells | Texpedloft synthetic batting welded to the top and bottom of the air chambers |
| Top fabric | 30D | 20D |
Shaded cells mark the row where one has a measurable advantage. Weight, thickness, girth and shape are left unshaded on purpose: heavier is sometimes tougher, wider is sometimes warmer, and calling a winner on those would be an opinion dressed as a measurement.
What each one does well, and costs you
Sea to Summit Ether Light XR Insulated
- Four inches of loft at 16.6 ounces — the best thickness-to-weight in this catalogue outside the Tensor Elite.
- The Air Sprung Cell grid stops the wobble that ruins most thick air pads for side sleepers.
- Five sizes across mummy and rectangular cuts, so the fit choice is real rather than nominal.
- The Airstream pump is integrated into the stuff sack, so there is no extra item to lose.
- Sea to Summit publishes the ASTM figure and explains the test on the product page, which is unusually straight.
- R-value 4.1 is lower than several lighter pads here — the XLite is 4.5 at 13 ounces.
- Four inches is a long way to fall if it deflates, and a tall pad in a low tent is a tight fit.
- $199 for the Regular puts it in the same bracket as warmer pads.
- The many-celled construction makes it slower to deflate and pack than a simple baffled pad.
Exped Ultra 6.5R
- 0.45 R per ounce is the best warmth-per-weight figure in this catalogue — better than the XTherm's 0.47 only in the sense that it does it for less money and more loft.
- Actually lighter than Exped's own 3R at more than twice the R-value, which is the single strangest line on this site.
- 3.5 inches of loft and silent batting insulation.
- Same $200 in M, MW and LW, so the wide version is free.
- Winter-capable without being a winter-only pad.
- The name says 6.5R and the tested figure is 6.9, which is confusing in the other direction from most marketing.
- 20-denier fabric on a pad that will spend nights on frozen ground and scree.
- $200, and the 3R below it is only $30 cheaper for half the warmth — the cheaper pad is the worse buy.
- Batting insulation adds packed bulk compared with film at the same R-value.