Sea to Summit Spark SP III.
850+ fill down with nano-level DWR treatment in an ultra-compressible package. Packs smaller than a Nalgene bottle for fast-and-light missions.
The Verdict.
Gavler Meta-Score
“The most compressible three-season bag on the market. Ultra-Dry Down nano treatment provides genuine moisture protection. Best for fast-and-light missions and warm sleepers. Cold sleepers should size down in temperature rating.”
The Gavler Verdict
Where to Buy.
Prices checked regularly
90-day price history
Price History
Steady at $359 for the entire 90-day tracking window — no increases, no discounts, across 91 tracked days.
Tracked daily across retailers. Vote Want itabove and we’ll alert you the moment the price drops.
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Precision Engineering
1 lb 9 oz / 4L Packed
Smallest-packing three-season sleeping bag in the mainstream market.
Nano-Level DWR
Ultra-Dry Down treatment coats individual clusters for 60% better wet-loft retention.
3D Side Walls
Maximizes loft volume without box-baffle bulk.
Technical Specifications
The Scoreboard
Best-in-class pack size. Temperature rating is the main caveat for cold sleepers.
Cast Your Vote
Do you think Sea to Summit Spark SP III deserves the #6 spot in Best Backpacking Sleeping Bags?
Global Critique
“Smallest-packing three-season bag we've tested. The Ultra-Dry treatment is measurably effective.”
“Perfect for fast-and-light trips where pack volume matters as much as weight.”
“The compressibility is remarkable — genuinely packs smaller than a Nalgene.”
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