Designed to optimize the performance and life of your printers, Unison Contract Cartridge delivers superior print quality page after page in your Lexmark MS331, MS431, MX331 and MX431. Special characteristics and performance attributes of Unison Toner's unique formulation enable shake-free performance, consistently outstanding image quality, long-life system reliability and amazing sustainability. Lexmark Return Program Cartridges are sold at a discount, vs. the prices of regular cartridges, in exchange for the customer's agreement to use the cartridge only once and return it only to Lexmark for remanufacturing or recycling. High-yield cartridge generates approximately 15,000 pages.Designed to optimize the performance and life of your printers, Unison Contract Cartridge delivers superior print quality page after page in your Lexmark MS331, MS431, MX331 and MX431. Special characteristics and performance attributes of Unison Toner's unique formulation enable shake-free performance, consistently outstanding image quality, long-life system reliability and amazing sustainability. Lexmark Return Program Cartridges are sold at a discount, vs. the prices of regular cartridges, in exchange for the customer's agreement to use the cartridge only once and return it only to Lexmark for remanufacturing or recycling. High-yield cartridge generates approximately 15,000 pages.