The Pilot FriXion Ball Slim Erasable gel pen features a simple and slim pen body shape design. The 0.38 mm extra fine tip also makes it a perfect choice for inline commenting as well as fine drafting. The tip is very smooth to write with. The pen uses thermo-sensitive gel ink which becomes invisible after friction created by the magic eraser at the back of the pen. Please note the ink will also disappear when exposed to heat but reappear when the temperature drops below -10?C. The pen has a sleek and stylish outlook and available in various vivid colours.