A pen consists of the barrel (the body), the filler (the ink container), the ball (found at the tip of the pen), the clip and the ink, which is thick and not soluble in water, so it resists a long time in the tanks without drying out, although it dries instantly when writing. The vast majority of cheap personalised pens for gifts are printed on the barrel because it is the part that is most visible, but you can also personalise the clip, which although smaller is very eye-catching.