Sea to Summit Spark 30 Sleeping Bag vs Sea to Summit Spark SP I
Weight and specs compared for 2026 — and which one to choose.
Ultralight 30°F mummy bag filled with 850+ loft down. Differential cut and ripstop shell deliver excellent warmth-to-weight ratio.
Ultralight 850-fill down sleeping bag rated to 25°C.
Building a pack? Add either one to your HikeLoad list, or drop its weight into the base weight calculator, and see what it does to your total weight.
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Sea to Summit Spark 30 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 85 g (18%) lighter than the Sea to Summit Spark 30 Sleeping Bag (482 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.