The material is synthetic fiber. Both hanhaba obi are single-layered, so I think they can be used layered. They can also be used as a single layer, so I think you can enjoy various ways of tying them. *We pay close attention to checking for stains, but there may be oversights. Also, as these items are stored at home, please refrain from bidding if you are concerned about odors or if you have sensitive personal opinions.