OKI - Cyan - original - drum kit - for C911dn, 931, 931dn. 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 and other consumables 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.