Your favorite fountain pen deserves an equally great ink that will enhance those beautiful swirls and strokes. This Dr. Ph. Martin's fountain pen ink is non-clogging and keeps your pens in the best of their health. This highly pigmented ink is non-spreading and archival grade, and is a must-have for your classic and elegant fountain pens. Details:Available in multiple colors1 oz. (29.5 mL)Archival grade, lightfast and non-cloggingNon-spreading, pigment based and waterproofDropper topNontoxicAP certifiedFor use with TWSBI Diamond 500, TWSBI VAC 700 and other fountain pens