The differences between a roller pen and ballpoint pen are that a roller pen uses water or gel-based ink while a ballpoint pen uses oil-based ink, and of course a roller pen gets its name from a small rolling ball at the tip of the pen that produces the actual markings. This particular pen is a gel roller ball pen. Roller pens have their advantages and disadvantages but some of the positive qualities of roller pens are that they write more smoothly and with bolder markings and take less pressure to make markings. These Customizable Roller Pens have standard promotional pen features and designs including pen top with clip, sleek body and standard size. However unique design features for these Customizable Roller Pens are colorful pen top designs, large imprint areas and quality silver body color.