Compare the documented 66 in manufacturer size and 66 in manufacturer size versions. This is a source-based specification comparison, not a field test or a current price ranking.
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The useful difference
Compare ISO comfort against ISO comfort only when both records provide it. A name such as 20°F and a lower-limit rating are different measurements. Fit and the pad beneath you can change the useful choice.
Exact versions compared
Western Mountaineering MegaLite — 66 in manufacturer size and Western Mountaineering AlpinLite — 66 in manufacturer size. Other sizes may change the result.
Specifications side by side
| Metric | Western Mountaineering MegaLite — 66 in manufacturer size | Western Mountaineering AlpinLite — 66 in manufacturer size |
|---|---|---|
| Name/label temperature | 30°F (-1.1°C) | 20°F (-6.7°C) |
| Comfort temperature | 32°F (0.0°C) | 25°F (-3.9°C) |
| Limit temperature | 22°F (-5.6°C) | 14°F (-10.0°C) |
| Listed weight | 1.44 lb (652 g) | 1.81 lb (822 g) |
| Maximum listed user height | Not verified | Not verified |
| Shoulder girth | 63.0 in (160 cm) | 63.0 in (160 cm) |
| Fill power | 850 | 850 |
“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 Western Mountaineering MegaLite 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 Western Mountaineering AlpinLite 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
Compare ISO comfort against ISO comfort only when both records provide it. A name such as 20°F and a lower-limit rating are different measurements. Fit and the pad beneath you can change the useful choice.
Open each record to inspect the source for the exact figure and its revision notes: Western Mountaineering MegaLite — 66 in manufacturer size; Western Mountaineering AlpinLite — 66 in manufacturer size. 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
- www.westernmountaineering.com
- www.westernmountaineering.com
- www.westernmountaineering.com
- www.westernmountaineering.com
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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