Polychromos pencils have particularly smooth leads which are waterproof and non-smudging. They are unsurpassed for light fastness. The leads themselves are adhered to the wood wrapping all of the way down the interior of the pencil so the leads will not slip out and they do not easily break and fall out of the wood. Colours are intense and absolutely beautiful! Every colour made using high quality pigments. The colours are rated individually for lightfastness- with either one two or three stars printed at the base of the pencil.