Dr. Ph. Martin's Bombay India Inks offer powerful color in a convenient dropper-stopper glass bottle. These highly pigmented India inks not only remain lightfast and permanent, but are also totally waterproof when dry. They adhere to nearly all surfaces and are non-clogging when used in pens. You can use this ink with technical drawing pens, airbrushes and dip pens.Details: Available in multiple colors 1 fl. oz. (29.57 mL) Archival quality, pigment-based ink Transparent and lightfast Non-clogging and waterproof Nontoxic and acid-free Dropper top AP certified Conforms to ATSM D-4236 For use with brushes, airbrushes, technical pens and dip pens