4 Inch White Foam Balls, Polystyrene for DIY Crafts, Art, School Supplies, Decorations (12 Pack) : Arts, Crafts & Sewing - Amazon.com
Amazon.com: Mega Crafts White Poly Craft Foam 12 Inch Ball, Durable, Solid Polystyrene Balls for Arts & Crafts, Ornaments, School Projects, Knitting & Party Favors, Great for Kids, Teachers & Artists :
Styrofoam Ball - Etsy
EB-020 Polyfoam Balls, Multi color, 2mm, 12g - Angels Craft