A combination of micro-pulverized pigments and black dyes make up this water-based ink. Can be diluted with distilled water. Compatible with dip pens, brushes, airbrushes, and fountain pens. Close cap tightly after use. Do not mix with acids, or use as tattoo ink. Not launderproof. To keep pens in good repair, clean with water or Higgins Pen Cleaner no longer than 1 week after last use. Shake well before use. Made in the USA