printing allows for custom foil titles and graphics to be permanently printed onto your spines. And we carry 6 colors and one primer. We have black and white matte and silver, gold, blue, and green metallic cartridges. The primer applies an undercoat that will greatly improve the quality of your printing. These work on clear and suede FoilFast title sheets. It's durable and scratch-resistant. And you'll get a lot of use out of these, since they come 5 to a pack.