AVS STORE &reg; Set of 12 Magnet Buttons with Smiley Face for Fridge, Magnetic White-Boards - Stick Notes, Photos, Charts and More Size: 3 cm Diameter; Material: Plastic and Magnets. Magnet Buttons with Smiley Face for home, office, schools etc. Use as markers to mark positions on whiteboards. Stick on fridge, white-boards or other iron surfaces. Stick notes, papers, photographs, charts and more.