Uni Posca PC-3M Marker 1.5mm Bullet tipped Multi-surface Water-based Non-toxic Permanent Grey The Uni range of Posca Markers all use a high-quality water-based ink which is waterproof and lightfast meaning long lasting results even when exposed to light. The Markers are highly adaptable as they can be used on a variety of surfaces ranging from glass to PVC to wood and cork, as well as giving permanent results on card and paper without the risk of any seepage. The Posca range come in an array of tips suitable for any project including pin, chisel, bullet and brush tips with most of them being replacable and and washable with warm water.