Sea to Summit Spark 30 Sleeping Bag vs Zpacks Classic Sleeping Bag 20F
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.
Check price Full details →Mummy-style sleeping bag rated to 20F (-7C) with 900-fill goose down. DCF outer shell for low weight and packability. Water-resistant treatment included.
Check price Full details →Sea to Summit Spark 30 Sleeping Bag vs Zpacks Classic Sleeping Bag 20F: which should you buy?
If saving weight is your priority, the Zpacks Classic Sleeping Bag 20F wins — at 347 g it is 135 g (28%) 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.