100% Mulberry silk duvet by Highland Feather features a 100% cotton casing with a 300 thread count. Filled with 100% premium Mulberry Silk, this All-Season lightweight duvet provides warmth and a soft, cozy feel. Silk is known for its moisture wicking and temperature regulating properties, which keeps you warm during winter nights and cool during summer nights. The natural properties of silk ensure that the duvet is not only hypoallergenic but also free from harmful chemicals. Ideal for sensitive skin.