Choosing duvets can be a little challenging. At Yvonne Estelle's we take the mystery out of down. The Inside ... The soul of every duvet is fill. All our our down duvets are filled with goose down of exceptional quality and purity. Down is the insulating fluff found under the chest feathers of waterfowl. Generally, the colder the climate and the longer the goose is allowed to mature, the larger the down clusters. We offer down duvets in four down types: White Goose Down (550 fill power), Hungarian Goose Down (650 fill power), Polish Goose Down (750 fill power and hypoallergenic), or Siberian Goose Down (800 fill power and hypoallergenic). Fill power indicates the number of cubic inches filled by each ounce of down. The more space an ounce of down takes up, the fluffier the duvet will be. The Outside ... The quality of fabric used to enclose a duvet can enhance or undermine its ability to loft, breathe and last. Ticking is the fabric sack that contains the fill of a duvet. All our duvets are made with down-proof, natural fiber ticking of exceptional quality.