Uni-Ball 8mm Chisel Tip Chalk Marker writes on and wipes off making it the perfect tool for writing on non-porous surfaces such as chalkboards and glass. Perfect for pub, and restaurant signs, its 8mm chisel tip gives you a thick, bold line and is great for large format work and bold hand-lettering. Not suitable for porous surfaces. Water-based paint pen Works well on non-porous surfaces such as chalkboards and glass Writes on and wipes off Perfect for pub, and restaurant signs Rain-resistant so your message can withstand the elements (within reason)