Material: Made of premium quality foam material and high density felt bottom, non-toxic,only the back side with high density felt bottom is magnetic.^Designed in a perfect size 7.5 x 4.5 x 2cm (2.95 x 1.77 x 0.79 inch), the eraser features small, lightweight, suitable for children and adults.^A good assistant with strong absorb-ability, they are not just erasers, but also can be used as magnets on whiteboard or any other magnetic surface, a handy necessary for classroom, school, home, office meeting.^To clean the whiteboard easily and effectively, just swipe the eraser with a little pressure to clean your whiteboard.^Package Include: 36 pieces magnetic whiteboard erasers in 4 colors(Red, Yellow, Blue, Green), 9 pieces for each color.