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Sea to Summit Ultralight Insulated vs Therm-a-Rest Hyperion 20

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

Therm-a-Rest Hyperion 20 is the lighter option — 28 g lighter than the Sea to Summit Ultralight Insulated (5% less weight). If grams matter to you, that is the one to beat.
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Spec Sea to Summit Ultralight Insulated Therm-a-Rest Hyperion 20
Weight 595 g · 0.595 kg · 1.31 lb 567 g · 0.567 kg · 1.25 lb
Brand Sea to Summit Therm-a-Rest
Category Sleep System Sleep System
Sea to Summit Ultralight Insulated
595 g

Insulated inflatable pad with R-value 3.7.

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Therm-a-Rest Hyperion 20
567 g

900-fill Hyperdry down mummy sleeping bag rated to 20F/-6C. 10D ripstop nylon shell with DWR treatment. Regular size.

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Sea to Summit Ultralight Insulated vs Therm-a-Rest Hyperion 20: which should you buy?

If saving weight is your priority, the Therm-a-Rest Hyperion 20 wins — at 567 g it is 28 g (5%) lighter than the Sea to Summit Ultralight Insulated (595 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.

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