standard-yield Ink Cartridge Delivers Outstanding Results Page After Page In Your Lexmark X2690, X4690, Z2490 And Z2390. Superior Lexmark Design Means Precision Pairing Between Printer And Cartridge For Value, Quality And Environmental Responsibility You Can Count On. Lexmark Return Program Cartridges Are Patented Print Cartridges Sold At A Discount In Exchange For The Customer''s Agreement To The License Requirement That The Cartridges Will Be Used Only Once And Returned Only To Lexmark For Remanufacturing Or Recycling. These Patented Cartridges Are Licensed For Single Use Only And Will Stop Working After Delivering A Fixed Amount Of Ink And/or Toner. Cartridge Yields Approximately 175 Standard Pages.