DetailsA bag you can trust to get you through single-digit nights. The KSB 0's 650 fill power down top and synthetic fill bottom provides an exceptional warmth-to-weight ratio. When the temperature drops below freezing and into single digits, you need a bag that eliminates excessive air pockets to achieve lasting warmth through the night. Flexible Stretch Baffles keep fill next to your body and stretch when you move, while Length Locks™ allow 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.