What is the difference between goose down?

Down is divided into duck down and goose down, with goose down providing slightly higher warmth than duck down under the same conditions. Down has three main performance indicators: the first indicator is the filling weight, such as a 400g goose down sleeping bag or a 1100g duck down sleeping bag. This weight does not refer to the weight of the sleeping bag, but to the net weight of the filled down; The second indicator is the content of down, which is composed of feathers and down fibers. The feathers provide support, while the warmth mainly comes from fine down fibers. The velvet content is expressed as a percentage, for example, 80 velvet indicates that the velvet content in 100 weight units is 80 units. Duck down generally has a maximum content of 85 to 90, while goose down can have a content of up to 90 to 95; The third indicator is the expansion degree of down, which refers to how many cubic inches an ounce of down has under a pressure of 68.4 grams. The higher the expansion degree of down, the better the insulation performance of the down. The expansion degree of domestic duck down is generally around 450, while the expansion degree of domestic goose down ranges from 450 to 600. The Andean mountain goose down imported from the United States has a velvet content of about 95% and a maximum expansion degree of 700 to 800. In the past two years, the popularity of goose down in the market has been increasing, but the quality is uneven. In terms of warmth, goose down is definitely better than duck down, because as we all know, the principle of warmth is mainly based on the amount of fixed air, that is, the fluffiness and thickness of things keep them warm. Down is the same, because of its structure, the size of down fibers directly affects the amount of fixed air volume. Generally speaking, the volume of goose down fiber is larger than that of duck down fiber, and the fixed air volume is also larger than that of duck down fiber, so it is naturally warmer than duck down. You can take a look on the market and see that the maximum temperature limit for 1500G duck down is -29 degrees Celsius. The minimum temperature limit for 1500G goose down is -40 degrees Celsius. Also, because ducks are omnivorous animals, there is a fishy smell in their fur. Although it can be eliminated through processing, it is said that the smell can still come back after one or two years, but it can still be tolerated. And geese are herbivorous animals, with no peculiar smell in their fur.