The fluorescent pen is divided into two types: water - based and oil - based.
The water-based pen is similar to the color pen, it is non-toxic, but it is not easy to dry. And the coverage is not good, some of the surface can't be written on, and the two colors will look dirty when folded together.
An oil pen is a synthetic solvent that USES alcohol to dissolve color. Some sensitive people get dizzy when they smell it. But it's easy to write and dry, covers well and costs less.
There are also some fluorescent pens with fruit aromas.