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Rab Mythic Ultra 20 vs Sea to Summit Spark SP I

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

No winner on weight yet. The recorded weights have not both been verified on the same basis. Size, included parts and single-item versus pair weights can differ. Check the linked sources before choosing a replacement.

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Spec Rab Mythic Ultra 20 Sea to Summit Spark SP I
Weight 440 g · 0.440 kg · 0.97 lb 397 g · 0.397 kg · 0.88 lb
Brand Rab Sea to Summit
Category Sleep System Sleep System
Rab Mythic Ultra 20
440 g

20-degree sleeping bag weighing 440g. Features TILT lining technology that reflects heat back to achieve superior warmth-to-weight ratio.

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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Rab Mythic Ultra 20 vs Sea to Summit Spark SP I: which should you buy?

The listed weights alone are not enough to choose between these products. Confirm the size, included parts and weight basis against each source; choose equipment for the function and fit you need.

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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