Extra Thick 4 inch Deep Duck Feather Matress TopperDuck feather and down is the most luxurious of natural fillings. This Duck feather and down mattress topper has 85% Duck feather, and 15% Duck down (the part which has the thermal, breathable properties). The 100% cotton cambric cover ensures the feathers do not stick out of the casing ensuring you get a perfect nights sleep. 85% Duck feather 15% down. The more down, the better the product , Extra Deep Depth: 4" 10cm 100% pure cotton cover, ensures