Ohto D1 Refill for small ballpoint pens and works perfect with Pen UNO. Fine nib 0.7mm with 0.35mm line width.
• Stainless Steel with Tungsten Carbide ball
• 0.7mm needle shape
• 0.35mm writing line width
• Soft Ink
• Length: 67.5mm
• Diameter: 2.3mm
• Weight: 1g