FeaturesNon-permanent marker1.8-2.5mm line widthVivid water-based inkCan be removed from chalk boards, windows and non-porous surfacesPack of 4The Uni-Ball UniChalk Marker is a non-permanent marker pen, which writes on and is easily removed from chalk boards, windows and other non-porous surfaces, including metal and plastic. With a 1.8-2.5mm line width, these markers use water-based paint to create vivid coloured writing with a medium bullet tip, ideal for creating eye-catching displays. For writing that is weather resistant, but which can be easily cleaned off with a damp cloth, choose a Uni Chalk Marker. This pack contains four white chalk markers.