Specification: Brand new Material: Metal Ink Color: Black/Blue Refill Length: 70mm (approx.) Refill Diameter: 2.25mm (approx.) Writing Thickness: 1.0mm (approx.) Usage: Yurn the black part in the direction shown by the arrow. Take out the ink pen refill. Tighten the new ink pen infill clockwise. Done. Package Included: 10x Crystal Refill Pens Note: Please allow minor error due to manual measurement. Due to the difference between different monitors, the picture may not reflect the actual color of the item.