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