A rollerball pen that allows for an airy light writing experience by controlling the ink flow rate according to the pressure of your pen.. The interior of the nib moves up and down with the pressure of your writing and is equipped with a special tip that allows you to control the ink flow. This allows you to write clearly without having to apply force... This special tip also allows you to write thick lines when you apply strength or lay it down. You can decrease the strength or stand it up for fine lines. Some of the different colors are used in the detailed images.