The KX-FA76 is a black toner cartridge from Panasonic designed for use with its KX-FL501, KX-FL521, and KX-FLM551 laser fax machines. It has utilizing powerful laser printing technology. This replacement cartridge prints sharp images and text. The KX-FA76 has a duty cycle of 2,000 pages (based on 5% average coverage) providing long lasting life even in heavy use environments. It is also easy to install and replace. Simply open the printer cover, insert the cartridge, and close the cover. One toner cartridge is provided per box. 2000 page yield black toner for the Panasonic KX-FL501 & 521 laser fax machines.