Boys Spiderman Spider Strike Design Reversible Bedding Sheets Set (Twin Bed) (Grey) Please note: This product is a UK import, the sheets supplied are 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 sheets for a duvet. High quality girls bedding set. Fiber: 100% Polyester Microfiber. Size - Duvet sheet: 53 x 79 inches.