its the HB graphite grading scale, for hardness and darkness of the graphite on paper. the higher the number, like a number 2 pencil, the harder the lead.
It just represents a shade of pencil. The scale goes like this: 9B-8B-7B-6B-5B-4B-3B-2B-B-HB-F-H-2H-3H-4H-5H-6H-7H-8H-9H Where there is a higher the B number, the darker and harder it is, while the...
H stands for Hard
B stands for Black
Pencils are graded according to hardness of the lead or softness. Example:
3H is very hard
2H is quite hard, but less hard than 3H
H is hard
HB is middle...