The outer fabric is 100% bamboo fabric. It feels very special because it's super soft and smooth, breathable, and naturally anti-bacterial and hypoallergenic. With excellent wicking properties, it even stays cool in the summer and keeps you warm in the winter.
The inner fabric is 100% cotton.
The filling is called Thinsulate from 3M, so it's lightweight and the quality is very good. This is also why it will stay fluffy overtime. If you like, you can read more about it here: