It uses a quality water based ink that is quicker to dry preventing unpleasant smudges its specially formulated to prevent the ink bleeding through on paper the ultra fine tip provides a crisp and clear 05mm line and has been reinforced with metal to prevent damage during use felt tip writing pen water based ink that dries quicker designed to prevent ink bleeding through paper ultra fine tip for crisp 05mm line metal reinforced tip to shield against damage ink colour blue pack of 12 pen