Sea to Summit Spark Sleeping Bag

No, the Spark is designed for mild conditions with a temperature rating of 45°F. It is best suited for summer backpacking, warm-weather thru-hiking, or as a lightweight liner in more temperate climates.

It is exceptionally compact. When fully compressed, the bag occupies just 2.4 liters of space, making it an excellent choice for ultralight setups where pack volume is at a premium.

The shorter zipper is a deliberate design choice to save weight and minimize heat loss. While it requires a bit more maneuvering than a full-length zipper, it is sufficient for sliding into the bag once you are used to the mummy shape.

The 10D nylon shell is treated to resist moisture, which helps protect the down insulation from condensation inside your tent or light mist. However, it is not waterproof, so you should still use a pack liner or dry bag to keep it completely dry during heavy rain.

The Spark uses an ergonomic mummy cut that balances weight savings with internal space. While it is designed to be efficient, it provides enough room for most sleepers to shift positions, though it will feel more snug than a rectangular bag.