Enjoy your Gel Pens for an insanely long time. The ink in each pen can be used a lot of times and will still flow smoothly. When the ink does finally run out, the fun could still go onsince on your coloring page. To ensure that your project doesn’t come to an unforeseen halt, the pen itself is made from transparent hard plastic, so you can see how much ink is still left in the pen. The etched grooves on the body ensure that the pen doesn’t roll away once placed on your work surface.