Nobody knows how to make consumables for your printer quite like
Xerox (the original manufacturer of your machine). As such the
genuine 109R00725 is the optimum choice for the Xerox Phaser 3121
and all other compatible printers mentioned on this page.
With a 3,000 page yield this Xerox 109R00725 black toner cartridge
offers a reasonable price per page. To see a full list of products
compatible with your printer and any alternatives to the Xerox
109R00725 we may stock, click your model number on this page.