... .international certification passed 1,Prouduct name:High-quality pencil leads;2,Hardness of pencil leads: 4H, 3H, 2H,H,HB,B ... R.S.c.H-3. Established in 1988, Shangzhi Pearl Pencil Industry Co., Ltd. is a manufacturer and trader specializing ... in the research, development and production of pencil leads, pencil boards, pencil and wedge joint boards, dressed lumbers, semi-finished ...