(90% down - 10% back feathers were used.) Goose down duvets - ideal for use in both summer and winter with their anti-sweat structure. Current duvet technologies still cannot achieve the comfort provided by natural goose down. You will enjoy your sleep with the soft texture of Goody Goose Series products using 100% natural goose down... It is the most preferred-softest-lightest and most hygienic filling material in the world. Goose down has a hygroscopic feature that absorbs excess moisture in the environment and releases it when needed. It provides a comfortable sleep by balancing heat and humidity. Goose down - the lightest filling material on earth - is long-lasting. It is a natural and comfortable filling material.