Pilot Hi-Tec-C RefillNote: Only fits regular Hi-Tec-C Pens. Not compatible with Hi-Tec-C Knock S pens.What are Hi-Tec C pens? Pilot Hi-Tec C pens are special pens that are currently very popular in Japan. They are highly sought after in the US, but are very difficult to find in stores. The fine tipped point of Pilot Hi-Tec C pens allow you to write with incredible precision. Moreover the ink is chemically formulated so that it will not bleed after it dries. Hi-Tec C fans immediately recognize the brilliant design of these pens. They are available in .25mm, 0.3mm, 0.4mm and 0.5mm sizes and in a variety of colors.