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Sea to Summit Spark SP I vs Sea to Summit Ultralight Insulated

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

Sea to Summit Spark SP I is the lighter option — 198 g lighter than the Sea to Summit Ultralight Insulated (33% less weight). If grams matter to you, that is the one to beat.
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Spec Sea to Summit Spark SP I Sea to Summit Ultralight Insulated
Weight 397 g · 0.397 kg · 0.88 lb 595 g · 0.595 kg · 1.31 lb
Brand Sea to Summit Sea to Summit
Category Sleep System Sleep System
Sea to Summit Spark SP I
397 g

Ultralight 850-fill down sleeping bag rated to 25°C.

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Sea to Summit Ultralight Insulated
595 g

Insulated inflatable pad with R-value 3.7.

Full details →

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Sea to Summit Spark SP I vs Sea to Summit Ultralight Insulated: which should you buy?

If saving weight is your priority, the Sea to Summit Spark SP I wins — at 397 g it is 198 g (33%) lighter than the Sea to Summit Ultralight Insulated (595 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.

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