The Spark I is the lightest and most compact technical sleeping bag Sea to Summit makes. It's an excellent summer bag whether you're hiking, bikepacking or cycle touring. It also works as a booster bag, slipping inside another sleeping bag to add warmth. The Sp I compresses down to the size of a grapefruit. Ultra light and mummy shape, it has everything you need to keep you warm and it will hardly take up any space.
