The Vango Apex 3 Sleeping Bag has been designed for 4-Season use and is made with Vango's most innovative, environmentally friendly fabrics to date. It features Polair® EcoNet Lining made from recycled fishing nets and EcoLoft® insulation, a recycled synthetic, engineered to imitate the characteristics of real down filling. This Omega shaped bag has been ergonomically tailored around the head and shoulders to retain heat and its unique Thermal Reverb causes heat to reflect back onto the body making this bag the very pinnacle of thermal efficiency.