Sea to Summit Spark Pro Down Sleeping Bag vs Therm-a-Rest Hyperion 20F/-6C (Regular)
Weight and specs compared for 2026 — and which one to choose.
Ultralight down sleeping bag at 765g with 900+ fillpower RDS-certified down, 15°F rating and Free-Flow Zip system for versatility.
Check price Full details →Ultralight 20F down mummy bag with 900-fill Nikwax Hydrophobic Down for fast-and-light backpacking.
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Sea to Summit Spark Pro Down Sleeping Bag vs Therm-a-Rest Hyperion 20F/-6C (Regular): which should you buy?
If saving weight is your priority, the Therm-a-Rest Hyperion 20F/-6C (Regular) wins — at 567 g it is 198 g (26%) lighter than the Sea to Summit Spark Pro Down Sleeping Bag (765 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.