Wedo 256126 Pen 4 colors (black / red / green / blue) with 4 Interchangeable Retractable mines (Matt chrome) (Import Germany) (Office Supplies)
For who does not know: there is a single push button for 4 colors. It works with a gravity pendulum system: To select a color, just hold the pen horizontally (or very much inclined), to make it turn on itself so as to have the icon of the visible col