Western Mountaineering
Western Mountaineering UltraLite Sleeping Bag
$660
Best Sleeping Bags · head-to-head
Western Mountaineering UltraLite Sleeping Bag vs Sea to Summit Spark SpII Ultralight Down Sleeping Bag
A sourced, side-by-side comparison. Sea to Summit Spark SpII Ultralight Down Sleeping Bag is cheaper at $409. Every spec and price links to its source.
Sea to Summit
Sea to Summit Spark SpII Ultralight Down Sleeping Bag
$409Cheaper
Which is better: the Western Mountaineering UltraLite Sleeping Bag or Sea to Summit Spark SpII Ultralight Down Sleeping Bag?
The Sea to Summit Spark SpII Ultralight Down Sleeping Bag wins 1 of the 1 specs we compare head to head; the other wins 0. The Sea to Summit Spark SpII Ultralight Down Sleeping Bag is the cheaper at $409. The Sea to Summit Spark SpII Ultralight Down Sleeping Bag both leads on specs and costs less — the straightforward pick.
See Western Mountaineering UltraLite Sleeping Bag on Amazon See Sea to Summit Spark SpII Ultralight Down Sleeping Bag on Amazon
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Full spec sheet
✓ marks the stronger figure where "more" — or "less", for price and weight — is unambiguously better.
| Spec | Western Mountaineering UltraLite Sleeping Bag | Sea to Summit Spark SpII Ultralight Down Sleeping Bag |
|---|---|---|
| US price | $660 | $409 |
| Brand | Western Mountaineering | Sea to Summit |
| Released | — | — |
| Temperature rating f | 20 | 28 |
| Insulation type | down | down |
| Fill power | 850 | 850 |
| Shape | mummy | mummy |
| Packed weight (lb) | 1.81 | 1.17 |
| Packed size | 7 x 13 in | 2.5 L (approx. 1-liter bottle size) |
| Zipper side | left or right | — |
| Product note | 850+ FP ethically-sourced premium goose down; USA made; full-length #5 YKK zipper; 6'0" version weighs 1 lb 13 oz | Lower limit 28F / -2C; comfort 38F / 4C; Ultra-Dry Down PFAS-free treatment; regular size; 530 g / 18.7 oz |
Sources — Western Mountaineering UltraLite Sleeping Bag: westernmountaineering.com (verified 2026-09-21). Sea to Summit Spark SpII Ultralight Down Sleeping Bag: advnture.com (verified 2026-06-20).
What's the difference between the Western Mountaineering UltraLite Sleeping Bag and Sea to Summit Spark SpII Ultralight Down Sleeping Bag?
Where the two actually differ on the specs we track (4 of 8). Matching specs are omitted.
- Temperature rating f: Western Mountaineering UltraLite Sleeping Bag 20 vs Sea to Summit Spark SpII Ultralight Down Sleeping Bag 28
- Packed weight (lb): Western Mountaineering UltraLite Sleeping Bag 1.81 vs Sea to Summit Spark SpII Ultralight Down Sleeping Bag 1.17
- Packed size: Western Mountaineering UltraLite Sleeping Bag 7 x 13 in vs Sea to Summit Spark SpII Ultralight Down Sleeping Bag 2.5 L (approx. 1-liter bottle size)
- Product note: Western Mountaineering UltraLite Sleeping Bag 850+ FP ethically-sourced premium goose down; USA made; full-length #5 YKK zipper; 6'0" version weighs 1 lb 13 oz vs Sea to Summit Spark SpII Ultralight Down Sleeping Bag Lower limit 28F / -2C; comfort 38F / 4C; Ultra-Dry Down PFAS-free treatment; regular size; 530 g / 18.7 oz