Down is a mixture of "feather" and "down". Feather is the hair piece, which plays a supporting role in the down and allows the down to rebound quickly; and the down is the down bud, which is the body and value of the down. The velvet flower is a three-dimensional spherical shape, which is composed of a velvet core and many filaments that radiate out, similar to a dandelion.

Velvet is made up of thousands of tiny scales, each of which is hollow. There are many knuckles on each velvet, and these knuckles are full of stagnant air. At the same time, a large amount of air is also fixed between the filaments and between the tufts. This is the secret of why down is so warm.