The genuine Lexmark 56F2X00 is part of the industry leaders unique Return Programme that reduces the cost of purchasing this black toner cartridge. By purchasing this eco-friendly toner you agree to return the cartridge (for free) to be recycled afterwards. As a extra high capacity original Lexmark toner cartridge, the 56F2X00 has a much higher capacity than other units that are also available for your mono laser printer.This original Lexmark 56F2X00 black toner cartridge has an estimated page yield of 20,000 prints. Once compatible machines (like the Lexmark MS421dn) believe the 56F2X00 toner cartridge is empty, the unit will cease to function, allowing you to take advantage of the free recycling scheme mentioned previously.