The Rotring Isograph Master Set, which demonstrates technical precision, contains everything you need for complex designs and drawings. The Isograph pens are designed for heavy-duty use and feature chrome-plated fine points that allow for precise detail. The pens are equipped with an internal refillable ink reservoir, making them ideal for those who use ink quickly. The line widths of the pens vary: 0.1 mm, 0.3 mm and 0.5 mm. Also included is a Tikky mechanical pencil for sketching as well as various accessories to ensure your drawings are technically perfect.