Size : 70mm x 3mm Replacement core for ultra-fine ballpoint pen with ball diameter 0.5mm Weight: 1 g Ink color : Black Refill lead for Oil based ink ballpoint pen. OHTO CO., LTD. is a Japanese pen manufacturing company selling the OHTO brand. The company was established in 1929 as a manufacturer of dyes and ink. In 1949, the company became a pen manufacturer. OHTO manufactured world's first pencil-shaped ballpoint pen with chrome ball. This is the first MADE IN JAPAN ball point pen. Also OHTO has developed world's first water-based ballpoint pen (present day Roller Pen,) as well as the world's first roller pen with ceramic writing ball, CERAMIC ROLLER PEN. [Technology] 1. Ceramic Writing Ball - Rust free, thus possess everlasting preservation stability. This rust free property gives instant and quality writing even if use the pen after many years kept in unused state. CERAMIC BALL is as hard as diamond but possess unlimited craters on its surface. These craters reserve the ink naturally and help to give fountain pen like smooth writing. 2. NEEDLE-POINT - a combination of low viscosity soft ink and needle shaped writing tip. Cutting type needle tip and a low-viscosity oil-based ink (soft ink.) By combining these two technologies, "NEEDLE-POINT" was born. Ink is different! Tip shape is different! [Products] 1. Ceramic Roller Pen 2. Soft Ink Roller Pen 3. Ballpoint Pen 4. Fountain Pen 5. Mechanical Pencil 6. Multi-function Pen 7. Drafting Pencil 8. Free Ink Roller Pen 9. Knock Roller 10. Roller Pen 11. Gel Pen 12. Marker 13. Refills 14. GACHUCK 15. Super Clip 16. Slide Clipper 17. Home Slide Clipper 18. Slide Clipper.