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Rab Mythic Ultra 20 vs Western Mountaineering AstraLite

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

Rab Mythic Ultra 20 is the lighter option — 14 g lighter than the Western Mountaineering AstraLite (3% less weight). If grams matter to you, that is the one to beat.
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Spec Rab Mythic Ultra 20 Western Mountaineering AstraLite
Weight 440 g · 0.440 kg · 0.97 lb 454 g · 0.454 kg · 1.00 lb
size 5'8" (180 cm), the shorter of two sizes (6'4" = 496 g); no Regular/Medium label on page
Brand Rab Western Mountaineering
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 →
Western Mountaineering AstraLite
454 g

Ultralight 3-season sleeping bag with 850fp down and 12D shell. Designed for fast-and-light alpine pursuits and long trail journeys.

See it in your base weight → Full details →

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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Rab Mythic Ultra 20 vs Western Mountaineering AstraLite: which should you buy?

If saving weight is your priority, the Rab Mythic Ultra 20 wins — at 440 g it is 14 g (3%) lighter than the Western Mountaineering AstraLite (454 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.

More sleep system comparisons

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