Sea to Summit Spark Sleeping Bag

No, the Spark is designed for warmer conditions with a temperature rating of 45 degrees Fahrenheit. It is best suited for summer backpacking or as a lightweight liner system in milder shoulder seasons.

The 850+ fill power goose down is treated to resist moisture, which helps it retain loft and warmth if you encounter damp conditions. While it is not waterproof, this treatment significantly outperforms untreated down when dealing with condensation or light humidity.

The Spark uses a contoured mummy silhouette designed to maximize thermal efficiency, which means it has a snug, athletic fit. If you prefer to sprawl out or sleep on your side with your knees up, you may find the interior space somewhat limiting compared to rectangular bags.

The 7D and 10D fabrics are incredibly thin to save weight, which is the trade-off for such a light pack size. While they are durable enough for standard backpacking use, you should be careful around sharp objects like zippers, thorns, or rough rocks to prevent snags.

The Spark is designed as a minimalist, individual sleeping system and does not feature a zipper compatible with other bags. It is intended to be used on its own to keep your pack weight at an absolute minimum.