This superior chalk is 95% pure calcium carbonate and free of foreign materials that work their way into the board surface causing scratching, streaking and pitting. Round stick 3-1/4" x 3/8" fits most chalk chucks. AP certified non-toxic. Each box includes 12 pieces of chalk. Sold as 36 boxes for a total of 432 pieces.

• Superior chalk is 95% pure calcium carbonate and free of foreign materials
• Round stick 3-1/4" x 3/8"
• Makes clean, smooth lines and erases easily
• For use on natural slate and similar surfaces