Childrens/Kids Ben 10 Ultimate Alien Duvet/Quilt Cover Set (Twin Bed) (Grey/ Green) Please note: This product is a UK import, this duvet cover supplied is slightly smaller than the standard US duvet size, it will fit but the duvet may fold at the edge when covered. This is not a comforter but a cover for a duvet. High quality kids branded duvet cover set. Fiber: 100% Polyester microfibre. Machine washable.