16x20 Cluster Fiber Throw Pillow Form Insert Made from 100% polyester cluster fiber fiber filling Considered to be one of the smoothest most lump free fibers available, cluster fiber consists of thousands of individual cluster balls inside each pillow which are free to move around and rearrange inside the pillow. This increases the life of the pillow since no particular section will matt down. Cluster fiber is also softer than traditional fiber and last up to 2 - 4 years longer. Machine washable Poly / Cotton Covering For best results this insert is recommended for 16x20 sham covers Made in USA