The Klymit KSB 20 Hybrid Sleeping Bag with 650 fill power down top and synthetic fill bottom provide an exceptional warmth-to-weight ratio. Flexible Stretch Baffles keep fill next to your body and stretch when you move, while Length Lock allows you to adjust the bag to your height, creating a comfortable cocoon of fill around your feet. Additionally, anti-snag, two-way YKK zipper opens from the bottom or top to easily control the flow of air.