Artline EK541T Twin Tip whiteboard Pen. 0.4mm-1.0mm writing widths, Polyacetal resin nib (0.4mm), acrylic fiber nib (1.0mm), Ideal for use on laptop whiteboards, or where a more defined line is required. Can also be used on OHP acetate.CODE WIDTH COLOUR EK-541T 0.4-1.0mm Black EK-541T 0.4-1.0mm Blue EK-541T 0.4-1.0mm Red EK-541T 0.4-1.0mm Green