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Sea to Summit Spark Pro Down Sleeping Bag vs Therm-a-Rest NeoLoft

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

Therm-a-Rest NeoLoft is the lighter option — 48 g lighter than the Sea to Summit Spark Pro Down Sleeping Bag (6% less weight). If grams matter to you, that is the one to beat.
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Spec Sea to Summit Spark Pro Down Sleeping Bag Therm-a-Rest NeoLoft
Weight 765 g · 0.765 kg · 1.69 lb 717 g · 0.717 kg · 1.58 lb
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 NeoLoft
717 g

Plush 10cm-thick insulated air pad with R-value 4.7, designed for car-camping-level comfort at a backpackable weight.

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

If saving weight is your priority, the Therm-a-Rest NeoLoft wins — at 717 g it is 48 g (6%) 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.

More sleep system comparisons