Compare the documented Large and Regular Mummy versions. This is a source-based specification comparison, not a field test or a current price ranking.
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The useful difference
R-value describes controlled thermal resistance; width and length decide practical fit. A higher R-value is not a measured temperature guarantee, and a thick pad is not automatically warmer. The listed R-values are 4.1 and 5.4, respectively; check each test-method note before treating that difference as comparable.
Exact versions compared
Sea to Summit Ether Light XR Insulated — Large and NEMO Tensor All-Season — Regular Mummy. Other sizes may change the result.
Specifications side by side
| Metric | Sea to Summit Ether Light XR Insulated — Large | NEMO Tensor All-Season — Regular Mummy |
|---|---|---|
| R-value | 4.1 | 5.4 |
| Listed weight | 1.33 lb (605 g) | 0.88 lb (400 g) |
| Length | 78.0 in (198 cm) | 72.0 in (183 cm) |
| Width | 25.2 in (64 cm) | 20.0 in (51 cm) |
| Thickness | 3.9 in (10 cm) | 3.5 in (9 cm) |
| Packed length | 9.4 in (24 cm) | 10.0 in (25 cm) |
“Not verified” is an unknown value. It is never zero or proof that a feature is absent.
Search the exact model names on Amazon
These are paid search-result links for the model names above. Confirm the variant on Amazon before ordering.
Search for Sea to Summit Ether Light XR Insulated and check the exact size, revision and seller details before ordering.
(paid link)Search this model on AmazonAmazon search results may include different variants or sellers. No price or stock is verified here.Search for NEMO Tensor All-Season and check the exact size, revision and seller details before ordering.
(paid link)Search this model on AmazonAmazon search results may include different variants or sellers. No price or stock is verified here.How to choose
R-value describes controlled thermal resistance; width and length decide practical fit. A higher R-value is not a measured temperature guarantee, and a thick pad is not automatically warmer. The listed R-values are 4.1 and 5.4, respectively; check each test-method note before treating that difference as comparable.
Open each record to inspect the source for the exact figure and its revision notes: Sea to Summit Ether Light XR Insulated — Large; NEMO Tensor All-Season — Regular Mummy. The comparison has 6 shared numerical fields. Consider your shelter floor, sleep position and expected conditions with the sleep system builder.
What this comparison cannot establish
Neither listing verifies live inventory, price, independent durability, noise, waterproof performance in a storm, or comfort for every sleeper. Where a manufacturer gives conflicting figures, the product record preserves the discrepancy and may omit a normalized number.
Sources and further reading
Source pages and product listings can change. Specifications were assembled from the supplied dataset as of October 30, 2026; current availability is not guaranteed.
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