Riva Home Reef Duvet Sheet and Pillowcase Set (Full) (Blue) 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. Part of the Reef range. 50% Polyester, 50% Cotton. Comes in sizes: Single/Twin (53 x 79in), Double/Full (79 x 79in), King/Queen (90.5 x 87in) and Super King/King (102 x 87in).