The Mt. Fuji-shaped toothbrush head is a large toothbrush head, but it spreads out at the end, so it doesn't hit your mouth when brushing your back teeth, so you can brush every corner.
The Mt. Fuji-shaped finger press on the handle can also be gripped firmly with a non-slip in the shape of a snowcap. If you hold it under the handle, you can also hold it with a pencil and brush it with the correct tooth brushing method.
The triangular-shaped toothbrush bristles remove dirt thoroughly
Since the cross-section of the bristles is triangular, it is easier to bend than normal hair, and because it has many corners, it scrapes out dirt firmly.