Ariel Duvet Cover by Sferra Linens. Ariel is a piece-dyed sateen woven in Italy from 100% extra-long-staple cotton, its smooth surface and featherlight hand setting it apart in the most unassuming way. A collection with no need for ornament, only the rare pleasure of something that feels as good as it looks. Fabrication: Sateen Fiber: 100% Extra-Long-Staple Cotton Look & Feel: Sleek, Silken, and Sheen Weight: Very Light