Stabilo OHPen Universal Permanent Pen, 1 mm (Medium Tip) - Black PRESENT WITH CONFIDENCE - Great presentation tools that will not smudge important slides or transparencies. VERSATILE - They will also write on almost any hard surface, so are perfect for any task you would normally need a marker for. PERMANENT AND NONPERMANENT - A choice of either water soluble or permanent ink to choose from in each color (black shaft indicates permanent ink, gray shaft indicates non-permanent, water-soluble) LONG LASTING - A cap-off time of up to 3 days VARIETY - Available in three tip sizes: superfine (.4mm), fine (.7mm) and medium (1mm)