This correction fluid uses new ink so you can use it without waking the main unit. In addition, the cartridge is economical. A correction ballpoint pen for both oil-based and water-based inks on the rear end knock pressurized method. Main Body, Front Shaft, Cap: Polybutylene Terephthalate, Knock/Rear Axis: Polypropylene, Nib: Stainless Steel, Oil-based Main Solvent: Methylcyclohexane; Contents: 0.07 fl oz (2 ml)