We recommend Posterman Chalkpens, Illumigraph Chalkpens & Acrylista Chalkpens for use on non-porous surfaces. All of our chalkpens are perfect for use on glass, tiles, chalkboards and blackboards. Available in a choice of waterproof chalk pens for external use and wet-wipe chalkpens for internal use. Use our waterproof chalkpens outside and remove the ink with our EaziKleen Chalkboard Pen Remover. Need chalkpen advice? Call 0161 763 1072 we will be happy to help!