Sea to Summit Spark SP III vs Therm-a-Rest NeoAir XLite NXT

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

Therm-a-Rest NeoAir XLite NXT is the lighter option — 355 g lighter than the Sea to Summit Spark SP III (50% less weight). If grams matter to you, that is the one to beat.

Spec	Sea to Summit Spark SP III	Therm-a-Rest NeoAir XLite NXT
Weight	709 g · 0.709 kg · 1.56 lb	354 g · 0.354 kg · 0.78 lb
Brand	Sea to Summit	Therm-a-Rest
Category	Sleep System	Sleep System

Sea to Summit Spark SP III

709 g

850-fill down sleeping bag rated to 0°C / 32°F.

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Therm-a-Rest NeoAir XLite NXT

354 g

Ultralight inflatable sleeping pad with R-value 4.5.

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Sea to Summit Spark SP III vs Therm-a-Rest NeoAir XLite NXT: which should you buy?

If saving weight is your priority, the Therm-a-Rest NeoAir XLite NXT wins — at 354 g it is 355 g (50%) lighter than the Sea to Summit Spark SP III (709 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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