Ball diameter: 0.5 mm. [Specification] Shaft: resin. With rubber grip / pen tip: airtight system / clip: binder clip. Ink type : Water-Based pigment. ZEBRA is a Japanese company developing and manufacturing writing instruments. ZEBRA has sales bases in various countries around the world and delivers high quality writing instruments to customers all over the world. ZEBRA has been making writing instruments for drawing letters and pictures over a long period of more than a century. [Origin of company name ZEBRA] Zebra (ZEBRA) is a very mild animal living in Africa's wilderness, even without the weapon individually protecting himself from the enemy. Therefore, zebras are always clustered, and they continue to cooperate consistently and keep living. The founder established ZEBRA as a trademark, hoping that all employees will unite firmly, like ZEBRA, will struggle to build writing instruments for cultural improvement and development. Furthermore, the trademark Zebra (ZEBRA) faces backwards means warmth innovation (to know old things, to know new things), the power of sum of people and the spirit of warm innovation are the two pillars supporting ZEBRA. [Products of ZABRA] Oil-based ballpoint pen / emulsion ballpoint pen / gel ballpoint pen / multicolor / multi-functional ballpoint pen / mechanical pencil / SHARBO (Sharp pencil+Ballpoint pen / reinforced ballpoint pen refill core / gel ball pen refill core / eraser marker / eraser marker / board marker / water marker / brush pen / highlighter pen / check series / correction tool / pen tip / oil ballpoint pen refill core / Mechanical pencil part mechanism / replacement eraser.