Pilot Frixion Ball Knock Retractable Gel Ink Pen, 0.5mm, 10 Colors (LFBK-230EF-10C) (3, A) Bang for the buck 3 pack of popular "Pilot Frixion Ball Knock Gel Ink Pen" with 10 colors. . 10 colors for black, red, blue, blue black, green, light green, orange, pink, light blue, and violet Erase and rewrite repeatedly without damaging documents. Note : Erasable pens are not recommended for use on legal or office documents.