If you weigh only a few grams but still value a restful sleep, the Spark might be the right sleeping bag for you. Filled with RDS-certified 850+ fill power goose down treated with a PFC-free Ultra-Dry down treatment, the Spark features a technical hood and a zipper draft tube to retain heat. For comfort, it has a super breathable 10-denier lining, while a 10D outer material with a PFC-free DWR coating, along with a highly water-repellent hood and footbox, keeps out wind and condensation. The model with a full-length zipper can be combined with an equivalent Women's Spark, providing the same comfort for couples.