The Zenith series down-filled sleeping bags are designed and built for high-performance. The Zenith is constructed using a durable, polyester ripstop shell with soft polyester liner and RDS certified 600-fill waterproof down. The design features a contoured hood and mummy shape which help seal in warmth. For added heat retention, the Zenith boasts an insulated chest and zipper baffle — keeping the warmth in and the cold night air out.