Rorito Jottek Gel and Ball Pens, Set of 10 Assorted Body Colours Jottek Gel and Feathersoft Gold Ball Pens, Set of 10 (5 Gel Pens, 5 Ball Pens) Fully Gripped for Comfort Holding Grip Waterproof Ink. A gel pen uses ink in which pigment is suspended in a water-based gel. Because the ink is thick and opaque, it shows up more clearly on slick surfaces than the typical inks used in ballpoint or felt tip pens. Gel pens can be used for many types of writing and illustration.