This superior Platinum Down 10.5 tog double duvet is filled with a luxurious blend of platinum duck down and feather which offers superb natural warmth without weight. The duck down fill is fluffier and lighter than feathers, which are the most effective at maintaining warmth. The feather fill duvet has a crisp and naturally breathable 100% cotton percale cover and is rated 10.5 tog in warmth, suitable for spring/autumn.