Super Hi-Polymer Lead Refills produce crisp lines of consistent darkness, smoothness and density in 0.5mm mechanical pencils. HB hardness is equivalent to a No. 2 pencil and is excellent for all general writing, including items to be faxed, photocopied and electronically scanned. Each super-strong lead writes as far as an entire wooden pencil and produces a dark line. A 30-piece tube is equivalent to 30 wooden pencils.