Designed for exact compatibility with OKI products, only OKI consumables ensure maximum performance, longevity and ultimate cost-effectiveness. Oki's ribbon cassettes, inkjet heads, toner and EP cartridges are an integral part of the fundamental design of its printer and fax products, combining with other key elements of their design to deliver optimum durability, reliability and print quality. This black toner cartridge is designed for the OkiFax 5800.