These chalk markers produce dustless markings with water-based, nontoxic and fade-resistant ink! Use them at home, at school and in the office…on chalkboards, dry-erase boards, light boards and windows…or on any nonporous surface indoors or out! Plus, you can easily wipe away the ink with a damp cloth…or use them as semi-permanent markers on paper and other porous surfaces. Set includes 4 markers in 4 colors; each marker measures 5 5/8" in length.