The Mezuri inkless pen is made of bamboo and has a ruler printed on the barrel (up to 11.3 cm). This pen does not require ink cartridges or refill. The pen's graphite tip is designed to leave visible traces as it makes contact with the writing surface. Choosing a pen made of bamboo promotes making more sustainable choices, and encourages the use of renewable materials. Writing length: 1500 metres. Nib size: 0.5 mm.