The Spark Pro has been optimized for comfort, versatility and light weight. Our highest-lofting down - 900+ fillpower RDS-certified goose down with a non-PFAS Ultra-Dry Down treatment - is wrapped in extremely breathable 10D fabrics. The Free-Flow Zip system ensures maximum ventilation and the flexibility to open the bag flat as a quilt. Zip a Spark Pro to a Women's Spark and share the comfort with your companion. Features RDS-certified, 900+ fillpower goose down with a non-PFAS Ultra-Dry Down treatment for maximum thermal performance Featherweight 10D nylon shell with non-PFAS DWR, and a highly breathable 10D nylon liner for enhanced comfort Technical hood, anatomical footbox and an ergonomic mummy shape - ultralight doesn't have to mean ultratight Free-Flow Zip System: YKK #5 side zipper with zipper plow for reliable, snag-free operation. YKK #3 footbox and shoulder zipper for minimal additional weight Vertical chest baffles, horizontal baffles lower half and base, box wall baffle construction throughout Front draft collar is fitted around the neck and oversized at the shoulders to retain warmth Sea to Summit Guarantee is offered for the Lifetime of this product