This Product by Quartet is ideal for use on whiteboards and nonporous surfaces. This set consists of black, red, green, and blue colored markers. Chisel tip marker point allows you to create thin or thick lines. This set of markers have a see-through ink gauge, which shows exactly how much ink is left in them. It has a roll-resistant cap, which prevents markers from going out of sight. You can use it in schools and workplaces for effective presentations and meetings and express thoughts and ideas beautifully. This Product flows steadily, writes smoothly, and erases easily.