Sea to Summit Spark Pro Down 30 vs Western Mountaineering AstraLite
Weight and specs compared for 2026 — and which one to choose.
Ultralight mummy bag rated to 30F (-1C) with 950+ fill-power Ultra-Dry Down. 10-denier shell, shoulder and footbox zippers for temperature control.
Full details →Ultralight 3-season sleeping bag with 850fp down and 12D shell. Designed for fast-and-light alpine pursuits and long trail journeys.
Full details →HikeLoad is reader-supported. As an Amazon Associate we earn from qualifying purchases, at no extra cost to you. Learn more.
Sea to Summit Spark Pro Down 30 vs Western Mountaineering AstraLite: which should you buy?
If saving weight is your priority, the Western Mountaineering AstraLite wins — at 496 g it is 123 g (20%) lighter than the Sea to Summit Spark Pro Down 30 (619 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.