Linkyo Replacement Brother TN-770 provides a sharp monochrome (black) text with a standard yield of 4500 pages. All the toner cartridges have to be inserted into the DR-730 drum unit in order to operate efficiently. A drum unit has a capacity of 12,000 pages and needs to be replaced after the use of 3 or 4 replacement toner cartridges. Linkyo offers compatible replacement toner cartridges online with a 100% Satisfaction Guarantee in print quality.