Sea to Summit Spark Pro Down 30 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 — 265 g lighter than the Sea to Summit Spark Pro Down 30 (43% less weight). If grams matter to you, that is the one to beat.

Spec	Sea to Summit Spark Pro Down 30	Therm-a-Rest NeoAir XLite NXT
Weight	619 g · 0.619 kg · 1.36 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 Pro Down 30

619 g

Ultralight mummy bag rated to 30F (-1C) with 950+ fill-power Ultra-Dry Down. 10-denier shell, shoulder and footbox zippers for temperature control.

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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 Pro Down 30 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 265 g (43%) lighter than the Sea to Summit Spark Pro Down 30 (619 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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