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Sea to Summit Ember Down Sleeping Bag vs Sea to Summit Spark SP I

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

Sea to Summit Spark SP I is the lighter option — 212 g lighter than the Sea to Summit Ember Down Sleeping Bag (35% less weight). If grams matter to you, that is the one to beat.
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Spec Sea to Summit Ember Down Sleeping Bag Sea to Summit Spark SP I
Weight 609 g · 0.609 kg · 1.34 lb 397 g · 0.397 kg · 0.88 lb
Brand Sea to Summit Sea to Summit
Category Sleep System Sleep System
Sea to Summit Ember Down Sleeping Bag
609 g

850+ Ultradry down sleeping bag rated to 9°C; packs to 5.1L with soft Thermolite liner and recycled shell fabric.

See it in your base weight → Full details →
Sea to Summit Spark SP I
397 g

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

See it in your base weight → Full details →

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Sea to Summit Ember Down Sleeping Bag vs Sea to Summit Spark SP I: which should you buy?

If saving weight is your priority, the Sea to Summit Spark SP I wins — at 397 g it is 212 g (35%) lighter than the Sea to Summit Ember Down Sleeping Bag (609 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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