First of all, down is the warmest natural material that keeps the human body protected from the cold.
Firstmadenyc uses the highest quality 90/10 duck down / feather for our packable down jackets. The 90%/10% down / feather ratio means that there is 10% feathers in your jacket which translates to less quills to poke through the shell.
It is practically impossible to have 100% down because of the fact that down is gathered specifically from the belly part of the duck. The architecture of "down" is different than that of "feathers". Feathers are flat and do not trap air as well as down. However, the perimeter part of the belly starts to form quills making the gathering of down impossible to be 100%. If someone is advertising 100% down, I would be very skeptical about the quality and legitimacy of the brand.
Therefore, we offer 90/10 down/feather - the best quality in the market. Also please remember that we make our jackets in the same factories as other famous brands.