Uni Ball R: E3 is a smooth-writing gel pen that erases cleanly and easily the R: E features heat-sensitive ink that turns invisible when exposed to heat by rubbing it with the plastic friction "eraser" In the pen's push button. The friction eraser produces no dust when used and doesn't wear out. Uni-ball R: E3 employs a “rotary select Knock mechanism”. the “rotary select Knock mechanism” is a new mechanism that rotates the shaft to select the color you want to use, knocks the rear end of the shaft, and feeds the lead. By using this mechanism, the conventional Multicolor ballpoint pen slide Knock lever was eliminated, and a slim shaft that was easy to grip and excellent in design was realized. If you set the color you use most often in advance, you can use it just by knocking without searching for the knock bar of the color you want to use. When writing, you can knock smoothly by pointing the pen tip downward, just like a general Knock Ballpoint pen. When erasing, simply turn the shaft upside down to activate the built-in “lock mechanism” and fix the eraser, so it can be erased firmly. Also, metal refills can be processed thinner than resin refills, so Adopting metal refills means that the amount of ink is approximately twice that of our resized resin refills even with thin refill diameters for