Inside the chunky aluminium barrel of each Pentel N50 permanent marker is quality Pentel indelible ink that writes smoothly on almost any surface, from plastic and metal, to ceramics and glass. The bullet tip writes a 1.5 to 2.0mm line width, which is ideal for general purpose use in industry or commerce. This pack contains 12 black markers. With this promotion, when you buy 2 packs of 12 markers, you get another pack of 12 absolutely free!