DUSTLESS - After special treatment, the chalk is dust-free. No longer stain your hands and floor like traditional chalk.Keeps children safe and clean during outdoor play and outdoor art projects. EASY TO USE - Our chalk pens for blackboard can be Used on ALL Non-Porous Surfaces, such as blackboards, mirrors, car windows, glass, plastic, metal, whiteboard. PLEASE MAKE SURE THE SURFACE IS NON-POROUS! ADJUSTABLE AND WRITE SMOOTHLY - Adjustable Chalk Clip Set insert chalk into the card slot and adjust the height to a suitable positon.And the wax pencil touch makes writing more fluid. EASY TO ERASE - After finishing your DIY with our chalk board markersjust simply use A WET CLOTH to erase without any residue!Gift choice for various kinds of festivals. PERFECT PACKAGING - Each piece of chalk has A SEPARATE CHALK cover to protect the chalk from breaking.And the chalk covers CAN BE REUSED to save money.