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Sea to Summit Spark Pro Down Sleeping Bag vs Therm-a-Rest Parsec 20F

Weight and specs compared for 2026 — and which one to choose.

No winner on weight yet. The recorded weights have not both been verified on the same basis. Size, included parts and single-item versus pair weights can differ. Check the linked sources before choosing a replacement.

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Spec Sea to Summit Spark Pro Down Sleeping Bag Therm-a-Rest Parsec 20F
Weight 765 g · 0.765 kg · 1.69 lb
size Regular, 15°F (-9°C) version
 820 g · 0.820 kg · 1.81 lb
size Regular
Brand Sea to Summit Therm-a-Rest
Category Sleep System Sleep System
Sea to Summit Spark Pro Down Sleeping Bag
765 g

Ultralight down sleeping bag at 765g with 900+ fillpower RDS-certified down, 15°F rating and Free-Flow Zip system for versatility.

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Therm-a-Rest Parsec 20F
820 g

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...

See it in your base weight → Full details →

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Sea to Summit Spark Pro Down Sleeping Bag vs Therm-a-Rest Parsec 20F: which should you buy?

The listed weights alone are not enough to choose between these products. Confirm the size, included parts and weight basis against each source; choose equipment for the function and fit you need.

See where both rank against everything else in this category on the lightest sleep system page, or browse the full gear weight database.

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