FAIRFIELD-Poly-Fil Micro Beads, FOB: MI. Micro Beads are made of 100% mini virgin expanded polystyrene beads. These beads are used in some of the most popular decorative pillows on the market today. Use this filler for stuffed animals; pillows; pet beds and craft projects. The advantage of using micro beads is the softer; smoother feel to anything you fill with them. This package contains 20oz: approximately 1/2 cubic foot. Made in USA.