Premium 800 FP down is hydrophobic, PFC-free, and 100% Responsible Down Standard (RDS) certified for traceability and humane treatment throughout the supply chain. Other features include Thermo Gills for draft-free temperature regulation, and a waterproof/breathable footbox and hood to protect you head to toe from tent wall condensation. Opposite-sided, full-length YKK no-snag zippers allow men's (left side zip) and women's (right side zip) models to be zipped together to create a double sleeping bag. A fabric set of 20D Nylon Ripstop DWR on the shell, an ultra-plush 30D Nylon Taffeta lining, and a 40D Nylon Ripstop OSMO DWR footbox offer a supreme sleep experience for the most serious ultralight adventures. NEMO - Kayu Men's Sleeping Bag