Pottery Barn Sky Muslin Duvet Cover + 2 Shams Versatile style to summer bedding. Lightweight and breathable, the comfy cotton layer is woven with lean lines in a soothing palette for a cool, coastal feel. Matching shams complete the look. Made of 100% cotton percale. A percale weave is noticeably denser and wears well over time. Duvet cover and shams reverse to a solid color. Machine wash in cold water.