Sea to Summit Spark 30 Sleeping Bag vs Therm-a-Rest Vesper 20 Sleeping Bag
Weight and specs compared for 2026 — and which one to choose.
Ultralight 30°F mummy bag filled with 850+ loft down. Differential cut and ripstop shell deliver excellent warmth-to-weight ratio.
Full details →900-fill hydrophobic goose down sleeping bag rated to 20°F/-6°C. Ultralight and highly compressible for three-season backpacking.
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Sea to Summit Spark 30 Sleeping Bag vs Therm-a-Rest Vesper 20 Sleeping Bag: which should you buy?
If saving weight is your priority, the Sea to Summit Spark 30 Sleeping Bag wins — at 482 g it is 68 g (12%) lighter than the Therm-a-Rest Vesper 20 Sleeping Bag (550 g). That said, the heavier option may justify the extra grams with more capacity, durability or comfort, so weigh the trade-off against how you'll use it.
See where both rank against everything else in this category on the lightest sleep system page, or browse the full gear weight database.