Sea to Summit Spark SP III vs Western Mountaineering Versalite 10°F

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

Sea to Summit Spark SP III is the lighter option — 141 g lighter than the Western Mountaineering Versalite 10°F (17% less weight). If grams matter to you, that is the one to beat.

Spec	Sea to Summit Spark SP III	Western Mountaineering Versalite 10°F
Weight	709 g · 0.709 kg · 1.56 lb	850 g · 0.850 kg · 1.87 lb
Brand	Sea to Summit	Western Mountaineering
Category	Sleep System	Sleep System

Sea to Summit Spark SP III

709 g

850-fill down sleeping bag rated to 0°C / 32°F.

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Western Mountaineering Versalite 10°F

850 g

850-fill down sleeping bag rated to 10°F (-12°C).

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Sea to Summit Spark SP III vs Western Mountaineering Versalite 10°F: which should you buy?

If saving weight is your priority, the Sea to Summit Spark SP III wins — at 709 g it is 141 g (17%) lighter than the Western Mountaineering Versalite 10°F (850 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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