Liquid Chalk Pens, 24 Coloured Chalk Markers for Children on Blackboards Wipeable,Water-based, Reversible 3mm Fine Tip with 30 Chalkboard Labels, Perfect on Window, Glass, Wood, Office Home Supplies : Amazon.co.uk: Stationery &
How To Use Chalk Markers On Glass - YouTube
Make a simple window decoration with uni-Chalk Markers - uni-ball