Posterman Wet-Wipe can easily be wiped off with a wet cloth and has a 6.0 mm medium cut tip. Best suited for indoor use on blackboards / handles, glass surfaces and whiteboard. The result is similar to chalk, but without scraping, the text becomes waterproof when it has dried. Ideal for shops, restaurants, pubs etc. You can write on windows, mirrors, ceramics, paper, glass, plastic, metal, wood, stone and much more. Zig Posterman has a very covering ink.