Marmot Hydrogen 30°F vs Sea to Summit Spark SP III

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

Both weigh the same at 709 g, so choose on features, price and fit.

Spec	Marmot Hydrogen 30°F	Sea to Summit Spark SP III
Weight	709 g · 0.709 kg · 1.56 lb	709 g · 0.709 kg · 1.56 lb
Brand	Marmot	Sea to Summit
Category	Sleep System	Sleep System

Marmot Hydrogen 30°F

709 g

Ultralight 800-fill down sleeping bag rated to 30°F.

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Sea to Summit Spark SP III

709 g

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

Full details →

Marmot Hydrogen 30°F vs Sea to Summit Spark SP III: which should you buy?

On weight these two are identical (709 g), so your decision comes down to features, fit and price. Check the full details and current price for each above.

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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