0.9

They have better "flow" when writing as the tip does not sink into the paper, as it happens with thinner ones. They allow for more pressure and thus can create a variety of tones in designs and calligraphic effects.

For writing, the values F, HB, B, 2B, 3B are recommended. The higher the value of B, the softer the pencil tip and the more intense the black color. The higher the value of H, the harder the tip and the lighter the black color.