Designed with low intensity users in mind, the standard capacity genuine Brother TN421BK carries a reduced amount of toner (and lower price tag to match). With an estimated 3,000 prints from the Brother TN421BK, a small office is sure to be happy using the black toner cartridge for an extended period of time.If your printer is compatible with the original Brother TN421BK but you are looking for a printer cartridge with a lower cost per page, be sure to click the link to your printers full listing on this page. Following this link you will find all products compatible with your Brother printer listed, including this genuine TN421BK.