★Please Note★ If you are purchasing this pen for the first time, please order the ink. This pen is not inked. The ink can be filled with either "745R-9" or "745R-009". It is found in "Martial Synthetic Ink". Double cap with built-in spring seal provides full protection from the air and completely prevents clogging caused by drying. In addition, the internal air pressure is adjusted to keep it in the best condition at all times, and it can handle sudden changes in atmospheric pressure, preventing any clamps from falling or leaking. The tip and middle point are specially polished to ensure a smooth writing experience that will never fade. Martial Matic is a streamlined drawing pen with one pen and one system that can be used with both cartridge ink and refillable ink. Line-draw, letters, and templates are all in one, so you dont have to have a separate pen for different systems and it is very economical. ★Line Width★ 0.02 inch (0.4 mm)