The 0.3 mm extremely fine tip allows you to write smoothly, even in fine writing.
The acro ink used for Acroballs has a viscosity that is 1/5 that of available oil-based ballpoint pens, making it a smooth ink that is close to water-based, and the balls rotate smoothly. The low viscosity of the ink means the ink supply to the pen tip is ample and penetrates deep into the paper fibers, making handwriting even and dark.
The grip of the Acroball is rubber, which is a soft and non-slip material. In addition, the surface has a tire pattern consisting of non-slip irregularities.