The Nanofiber Comforter has a box-stitch design that keeps the fill from shifting and creating cold spots. Use with or without a duvet cover. Made via nanotechnology, Nanofibre resists water and stains while retaining 100% of the natural feel of the fabric. Unlike other comforters, Nanofibre protects against spills of all types. Nanofibre is not a coating and will not wash out, so the product is long lasting.