100% Responsible Down: The ultimate natural insulation, down provides maximum warmth with minimum weight. The structure of down creates loft and fill power rating is a measurement of this loft. The higher the fill power, the less actual down insulation will be needed to maintain the temperature rating. 686 100% Responsibly Sourced Down ranges from 550 to 700 fill power. We ensure, through third party certifications, that all of our 100% Responsible Down originates from humanely treated ducks and geese and does not come from animals who have been subjected to excessive harm like live-plucking.