A down jacket without feathers is called a space down jacket. Space down jacket is a gimmick, without feathers, it is a kind of fiber cotton, a cotton coat of space cotton, not a down jacket. Down cotton is hollow cotton or silk cotton, not real cotton or pure down. Distinguish between down jackets, you should know that down is the abdomen of waterfowl, including geese and ducks. Down is like a reed flower, and the flake is called a feather.