Uni-Ball 2.5mm Bullet 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 broad bullet tip makes this pen a great all-rounder, good for hand lettering and bold, robust drawings. 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)