Spark SP II Sleeping Bag
Sea to Summit Spark SP II Sleeping Bag Review
Tested and reviewed for bikepacking use
The Spark SP II is a traditional mummy bag that packs down to the size of a water bottle. The 850+ fill Ultra-Dry Down resists moisture, and the differential cut reduces cold spots. One of the most compressible bags available.
Who Is the Sea to Summit Spark SP II Sleeping Bag Best For?
Bikepackers who prioritize packed size above all else. If that describes your riding style, the Spark SP II Sleeping Bag should be at the top of your shortlist. It sits in the Sleep Systems category alongside 11other products we've reviewed.
How It Compares
At 520g and $299, the Spark SP II Sleeping Bag is 270g heavier than the lightest option in this category (the Therm-a-Rest NeoAir UberLite at 250g). The most budget-friendly option is the Klymit Static V Lite at $65.
The price-to-weight ratio comes in at $58 per 100g — a premium price point, but you're paying for quality, materials, and design that justify the investment for serious bikepackers.
What We Like
- +Incredibly compressible — water bottle size
- +850+ Ultra-Dry Down
- +Well-designed hood and draft collar
- +Excellent for side sleepers
Watch Out For
- −28F limit is optimistic in practice
- −Narrow cut won't suit all body types
- −Pricey for a 28F bag
The Bottom Line
The Sea to Summit Spark SP II Sleeping Bag earns a 4.3/5 rating. It's a solid performer that does most things well. Incredibly compressible — water bottle size is the standout feature, though 28f limit is optimistic in practice is worth considering before you buy.
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Sleeping bags, quilts, and pads that pack small and keep you warm on the trail.