Pottery Barn Kids Hydrocool Down-Free Duvet Insert Twin White. This duvet insert is perfect for the summer months! It’s light weight, cooling, and feels like you’re sleeping on a cloud! You deserve to sleep well, and integrating this duvet insert at bedtime will be just what you need to sleep comfortably each night. 100% cotton striped damask shell. Item is new in bag and is stored in a non smoking and pet free home.