The HB grading scale determines the blackness and hardness of the pencil. Any pencil with a number followed by H will be harder and offer a lighter color, while pencils labeled using a B will be softer while offering a bolder color. Even if the number is the same, the quality of color and line will be vastly different. If you are unsure of which option to choose, consider your drawing needs. Alternatively, look at investing in a set of pencils that offer a wider variety.