Brother's TN3390 Black Toner Cartridge is specially formulated to ensure quality, high resolution results. With Brother laser machines the toner and drum units work independently so when one unit runs out, you don't have to replace both, resulting in reduced waste and significant cost savings. With a super high page yield of approximately 12,000 pages (four times the yield of the standard cartridge), Brother's toner cartridges provide excellent value for money.