Sakura Knock Gel Ink Ballpoint Pen, Ball Sign Knock 04, 10 Color Assorted (GBR154-10) Sakura Knock Gel Ink Ballpoint Pen, Ball Sign Knock 04, 10 color assorted Model - GBR154-10 Knock type gel ink ballpoint pen from Japanese stationary manufacturer Sakura, 15 colors available as the series