Page Yield*: (45,000 pages) compatible with Lexmark 521 Laser (Black) (per cartridge) *at 5% coverage (ISO/IEC standard) Package Contents: 2 x 521 Black compatible toner cartridges Extra High Yield 52D1000 Compatible withl: Lexmark 521, 52D1000 Product name: LD Products 521, 52D1000 Compatible Toner Cartridge replacement for Lexmark 521, 52D1000 Toner cartridges for Lexmark 52152D1000 Professional compatible replacements manufactured by LD Products. Lexmark is a registered trademark of Lexmark and is not affiliated with and does not endorse LD Products