Non-porous Ceylon graphite cores are dense and durable. The core is "Carbo-Welded" to withstand four times the normal point pressure. The specially treated cedar wood casings sharpen easily. Pencils are pre-sharpened.
Darkness Scale of drawing pencils:
(darkest and softest lead) 6B, 4B, 3B, 2B, B, F (medium), H, HB, 2H, 4H, 6H (hardest and lightest lead)