White Duck Feather Topper. Our duck feather filled mattress topped is an easy way to add luxurious comfort to your bed. Looking for a way to make your mattress more comfortable? Our duck feather filled mattress topped is an easy way to add luxurious comfort to your bed. Naturally breathable cotton cover. Cover: 100% Cotton. Filling: 100% Feather. Thickness: 5cm (2 inch) approx. Machine washable Pure cotton cover Feather filled Enhances the comfort of your bed