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Sea to Summit Ultralight XR Insulated (Short) vs Zpacks Classic Sleeping Bag 20F

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

Zpacks Classic Sleeping Bag 20F is the lighter option — 43 g lighter than the Sea to Summit Ultralight XR Insulated (Short) (11% less weight). If grams matter to you, that is the one to beat.
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Spec Sea to Summit Ultralight XR Insulated (Short) Zpacks Classic Sleeping Bag 20F
Weight 390 g · 0.390 kg · 0.86 lb 347 g · 0.347 kg · 0.77 lb
Brand Sea to Summit Zpacks
Category Sleep System Sleep System
Sea to Summit Ultralight XR Insulated (Short)
390 g

Ultralight insulated sleeping pad at 13.8 oz (390g) for 66-inch length with 3.6 R-value, lightest inflatable option available.

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Zpacks Classic Sleeping Bag 20F
347 g

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.

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Sea to Summit Ultralight XR Insulated (Short) 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 43 g (11%) lighter than the Sea to Summit Ultralight XR Insulated (Short) (390 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