Uni Paint Markers are high-grade oil-based paint markers designed to write on any surface without losing their vivid colour. The world's most popular paint marker, extensively used by professionals and industry. Does not contain sulphur, chlorine or silicon. Completely waterproof, the ink doesn't run even if the surface used is heated. Makes a fantastic weatherproof garden marker - use the PX-21 or PX-203 for plant labels etc. Available in four nib sizes and a wide range of colours.