Sea to Summit Spark 30 Sleeping Bag vs Western Mountaineering AstraLite
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 3-season sleeping bag with 850fp down and 12D shell. Designed for fast-and-light alpine pursuits and long trail journeys.
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.
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 30 Sleeping Bag vs Western Mountaineering AstraLite: which should you buy?
If saving weight is your priority, the Western Mountaineering AstraLite wins — at 454 g it is 28 g (6%) 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.