The unique dry safe ink formula allows the cap to be left off for up to 48 hours without drying out (in controlled tests). The alcohol based pigment ink in the Artline 577 has a non offensive low odour and provides dense bold colours. | Perfect addition to meetings, classes and tutorials | Suitable for use on electronic whiteboards | Bullet nib with a 2 mm line width | Features dense bold colours | Made of Plastic Barrel