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Images: Sea to Summit and its retailers. Used for product identification.

Sea to Summit

Sea to Summit Spark -1 °C

A 510 g summer-to-shoulder-season bag for fast-and-light trips.

Weight
510 g
Comfort
+4 °Climit -1 °C
Packed
8 L sack, ≈ 4.5 L compressed

Best price found

£270.87

at Alpinetrek · In stock · RRP £386.95

View Deal
  • TrekittIn stock · RRP £400.00£320View Deal
  • Sea to Summit UKOut of stock at check£400View Deal

Prices checked 31 October 2026. We may earn a commission on these links.

  • 850 FP down
  • Hydrophobic down
  • RDS down
  • Draught collar
  • Box-wall baffles

Specifications

Weight
510 g (536 g long)
Packed size
8 L sack, ≈ 4.5 L compressed
Comfort
Comfort +4 °C / limit -1 °C
Fill
850 FP goose down, 265 g fill
Shell & construction
10-denier nylon shell and lining; Hybrid: box-wall baffles over the top half…
Rating Standard
EN 13537 limit; comfort figure from retailers
Fill Note
850+ fill power RDS-certified goose down with PFC-free Ultra-Dry Down…
Zip
Half-length #5 YKK zip with zip-plow and two sliders
Manufacturer page →

Pros & cons

  • Outstanding warmth-to-weight at about 510 g and packs very small
  • Roomier mummy cut than most ultralight bags, suits different sleeping positions
  • Anti-snag zip-plow and water-resistant hood/footbox fabric
  • Half-length zip limits venting and stops it opening flat as a quilt
  • Very thin 10D fabric needs care; high RRP

Sources for this product

  1. 1Sea to Summit UK product page
  2. 2Trekitt listing
  3. 3Alpine Trek listing
  4. 4bikepacking.com review, 10 Oct 2024

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