For those who want to sleep well but carry light, the Spark -1C down sleeping bag from Sea to Summit is a reliable companion. The ultra-thin outer material of the sleeping bag and the strategically placed down should not mislead you about how well this sleeping bag retains the body heat of its users. Filled with RDS-certified goose down with 850+ fill power and treated to be PFC-free, the Spark -1C offers optimal thermal insulation from late spring to autumn. The technical hood and zipper cover keep the warm air inside the sleeping bag, while the silky-light inner fabric ensures comfort and maximum breathability. The outer material of the Spark -1C is made of lightweight 10D nylon, and the water-repellent hood and foot box feature a PFC-free DWR coating to protect against wind and condensation. The sleeping bag can be compressed to save space and comes with a silicone-coated compression sack and a storage bag. Weighing only 493 g (regular size) and with a compressed volume of 4.5 liters, it is ideal for trips where every gram counts.