Product Introduction: Holder type so that your hands wont get dirty. Uses: Building marking chalk (Features) • Compared to new writing instruments that do not release powder, it does not volatilize and does not become volatily, so it can be used 2 to 3 times more than a marker. • Can be used on whiteboards and window glass, and can be used with a wet cloth or dedicated cleaner. [Precautions] Cannot be used with chalkboards. Note (Disclaimer) > Please read / Cannot be used with chalkboards. Even on smooth surfaces, try on an inconspicuous surface before using.