Sea to Summit Spark Pro Down 30 vs Therm-a-Rest Parsec 20F
Weight and specs compared for 2026 — and which one to choose.
Ultralight mummy bag rated to 30F (-1C) with 950+ fill-power Ultra-Dry Down. 10-denier shell, shoulder and footbox zippers for temperature control.
Updated 2026 ultralight 3-season sleeping bag with 900-fill Muscovy hydrophobic down. Comfort rating -6°C. Refined baffles for improved loft and simplified inte...
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Sea to Summit Spark Pro Down 30 vs Therm-a-Rest Parsec 20F: which should you buy?
If saving weight is your priority, the Sea to Summit Spark Pro Down 30 has the lower listed weight — at 619 g it is 201 g (25%) lighter than the Therm-a-Rest Parsec 20F (820 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.