Sea to Summit Spark Sleeping Bag

The Spark is rated for 45°F, making it a dedicated summer bag. If you are camping in shoulder seasons where temperatures might dip below that, you will likely need to pair it with a sleeping bag liner or wear extra layers to stay comfortable.

The down is treated with a non-PFAS water-repellent coating, which helps it resist moisture and maintain loft better than untreated down in damp conditions. While it is not waterproof, this treatment is a significant advantage for managing internal condensation inside a tent.

The Spark uses a technical mummy cut designed to minimize weight and maximize thermal efficiency, so it is a closer fit than a rectangular bag. If you are a restless sleeper who prefers a lot of room to move your legs, you may find the fit snug.

The 10D nylon is chosen specifically for its ultralight weight, which means it is thin and delicate. It is durable enough for standard backpacking use, but you should be careful around sharp objects like zippers, thorns, or rough rocks to avoid snags.

It is exceptionally compact, with a compressed volume of just 2.4 liters. It is designed to take up minimal space in your pack, making it an excellent choice for ultralight setups where every liter of capacity counts.