“4H and 3B” represent the degree of hardness and softness of a pencil lead.
The pencil with graphite as the main material can be used for drawing and writing.
The hardness mark of graphite lead core is usually “H” for hard pencil, “B” for soft pencil, “HB” for soft pencil, and “F” for pencil with moderate hardness between HB and H.
Graphite pencils are divided into 6B, 5B, 4B, 3B, 2B, HB, F, H, 2H, 3H, 4H, 5H, 6H, 7H, 8H, 9H, 1H.
The bigger the number in front of the letter is, the harder or softer it is. Of the 18 hardness grades, 6B is the softest and 10H is the hardest.
In addition, there are 7B, 8B and 9B3 soft pencils to meet the special needs of painting.