When it comes to extreme adventuring such as mountain climbing, portaging and other recreational journeys requiring lightweight supplies that are easily toted around, sleeping bags are far from compact; that is, until the Sea to Summit Spark SPI was created. It is a revolutionary sleeping bag that rolls up so tightly, it can fit into the palm of a person's hand.
Ideal for summer activities such as cycle touring and ultra-light hiking, the Sea to Summit Spark SPI is made out of a Pertex Quantum shell, nylon liner and 850+ loft goose down. Incredibly lightweight, is very warm in spite of its compactness. Nevertheless, its size and temperature rating means it can also work well as a booster bag for added warmth.