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.