Bilipala 4Pcs Colored Plastic Magnetic Chalk Holder Case Cover for School Office One package includes 1*green, 1*blue, 1*yellow and 1*red chalk holders, 4 in total Magnetic chalk cases can adsorb on a magnetic chalkboard or whiteboard. Eco-friendly, easy to carry and use, suitable for circular chalks, diameter between 8mm~10mm. Chalk covers can reduce the pollution of chalk ash to hands and clothes. Size:3.74*0.98 inches.