The Kassa Liquid Chalk Markers are the ideal tool for drawing or writing on chalkboards (best with the Kassa Chalkboard Decal, also sold on Amazon), glass, windows, and almost any imaginable surface. These chalk pens are child friendly (water based, non-toxic), great as bistro chalk markers, and will simply brighten up your life for any project that you desire. The chalkboard markers are wet wipe and easily erasable (for non-porous surfaces). CHALK MARKERS Dustless and Fluorescent chalk pens. The Kassa Liquid Chalk Markers work best with the Kassa Wall Sticker Chalkboard Contact Paper. FLUORESCENT COLORS These markers dry fast and are easily erasable. WORK ON Glass markers and window markers. Work on: varnished wood, non-porous chalkboards, chalkboard contact paper, appliances, whiteboards, counter-tops, stainless steel, glazed ceramic tile, and more! WARNING It is always recommended to test the chalk marker on a small surface, in order to ensure that it will erase. Not recommended for porous chalkboards or chalkboard paint.