Sea to Summit Spark SP I Sleeping Bag Shell: 10D UL Nylon treated with DWR Liner: 15D nylon soft touch, high density weave 850+ loft Ultra-Dry Down (90/10 European goose down)850+ loft Ultra-Dry Down (90/10 European goose down) 1/3 length #3 YKK zipperf Sew-through transverse baffle construction