Ultra-light and technical, our Spark Series bags are designed to keep you as warm as possible while minimising packed weight and size.

The Spark Series spans everything from an ultralight liner to an expedition weight mid-winter bag. While the end usage is very different, they reflect a design ethos of matching weather conditions to the lightest bag possible.

The secret to the impressive performance is a combination of premium materials and careful design. The RDS 850+ Loft premium goose down, light-gauge #3 YKK zip and high performance 10D Nylon shell and 7D lining fabrics, set the stage for superior performance. These materials are combined with a contoured mummy design for efficient insulation, and that mummy design is then tweaked for each model to best fit the use scenario.

Their Ultra-Dry Down water-repellent treatment protects the down from external moisture and condensation from the inside of the bag, virtually eliminating the negative effects moisture has on down. All Sea to Summit Down Sleeping Bags use Responsible Down Standard (RDS) certified down. The Ultra-Dry Down protection also makes the Spark an impressive hard-alpine or adventure racing bag, where every gram is counted and down has never been a viable option.


Ultralight 7D and 10D fabrics for minimal weight and packed size
RDS 850+ Loft Premium Goose ULTRA-DRY Down for maximum insulation value
Contoured mummy shape for comfort and efficient insulation
Vertical chest baffles prevent down migration and cold spots
Uses a full box baffle construction to accommodate extra down and reduce cold spots
Expedition mummy bag sizing provides extra space for layered clothing or extra wriggle room
Vertical baffles on chest optimises positions of down to prevent it moving during use
Full side zip with two sliders provides easy access and extra ventilation options
Zipper draft tube, hood and front neck draft collar to prevent warmth being lost when it’s needed
Includes lightweight Ultra-Sil Nano compression bag for compact storage


Shell: 100% Nylon, Lining: 100% Nylon, Primary Filling Material: GOOSE DOWN (Min. 90% Down), Stuffsack: 100% Nylon excluding Trims

Size Variation Regular Long
Recommended User Height up to 183cm up to 198cm
Packed Dimensions 18 x 40cm 18 x 40cm
Volume Compressed 6.6L 7.7L
Compression Sack Volume (Compressed) 10 to 3.3L 10 to 3.3L
Weight 880g 985g
Fill Weight 620g 700g
Internal Chest Circumference 155cm 162cm
Internal Hip Circumference 135cm 142cm
Internal Foot Circumference 94cm 100cm

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