Pilot Frixion Ball Knock Retractable Erasable Gel Ink Pens,fine Point, - 0.5 mm - Blue Ink- Value Pack of 10 Combines the convenience of a retractable with the incredible FriXion erasable gel ink Erase and rewrite repeatedly without damaging documents - Eraser is at the top of the pen, tip is retractable by pressing clip down Unique Thermo-Sensitive gel ink formula disappears with erasing friction