Seamless design, using the highest quality materials & lubricants, minimizes print head wear. Designed for precise compatibility with Oki's products, & manufactured to the highest possible standards, only Oki consumables ensure maximum performance, longevity & ultimate cost-effectiveness. Seamless design, using the highest quality materials & lubricants, minimizes print head wear. Features Oki Black Ribbon 4 Million Characters For use with Microline 5520; 5521; 5590 / 5591