As a hearing aid professional, I did not like the otoblock placement tools that were available on the market. They were big, heavy and the tip broke all the time.
Humans have used pens for hundreds of years, which allows for the most precise movements, so a pen-like tool is needed.
But it was necessary to keep the thinness of the tip which places the otoblock and to maintain the field of vision as much as possible (because an auditory canal may be small).
This is why the curette holder is made of an optical fiber and a colored covering material (blue or black).