Question: what is the difference between h and hb lead?
Answer: HB GRAPHITE SCALE The second graphite grading scale is known as the HB scale. Most pencil manufacturers outside of the U.S. use this scale, using the letter “H” to indicate a hard pencil. Likewise, a pencil maker might use the letter “B” to designate the blackness of the pencil's mark, indicating a softer lead.