These chalks can be safely used by us. The cleverly designed brings us a comfortable using experience. The included chalk holder can prevent the chalk from cracking, effectively improving the use rate of chalk and reducing waste.These chalks are widely used in school, classroom, kindergarten, office and home, and so on. Features -Color:Random Color -Material:Gypsum - Size: 19.50X15.00X11.00cm/7.66X5.89X4.32in - The chalk produces less, safe for use by children and adults, and making it easier to clean up after use. - Abundant quantity chalks, enough to meet your daily and replacement use, can also share with others. - The included chalk holders avoid the child put the chalks in the mouth, and very convenient for adults to use. - Chalk is made of reliable gypsum, prevents the chalk from breaking or crumbling, which can also reduce dust. - The chalk set come in bright colors, making it perfect for art projects, school, and other applications. Package list: Chalks 5 x Chalk Sleeves 1 x Eraser 1