Protect artwork and erase in detail with these quality, precision erasers in a pen-style holder. Tombow Mono Zero Erasers will not damage paper and are available in two shapes for a variety of erasing options. The eraser advances by clicking the other end of the pen-style holder. The holder includes a convenient clip for erasing on the go. The round eraser has a 2.3 mm diameter and the rectangular eraser has a 2.5 mm diameter.