It doesn't erase at all, except with alcohol or acetone. It has 2 writing options (normal and fine). The normal one is just right for my taste, but after moderate use, the thickness of the writing increases (the tip flattens). However, it lasts quite a while and is light in the hand.

For 15 years now, I have been using these markers for sketching. With one pencil, one black, one blue, and one green in the case, you can capture an entire city if you want. What I loved from the very beginning is the dual tip that allows you to go from detail to bold outline without carrying a whole bookstore in your bag. Basically, if you reduce sketching to the absolute basics with a small sketchbook, a pencil with an eraser, and one black marker like this, you have all the tools to capture any sketch you want, wherever you are.

It has 2 tips, one thin and the other slightly wider, they write on any surface, very good and useful. Two in one!