Each component of a Brother laser product is integrated within Brother's hardware to ensure the quality and reliability we stand for. All Brother genuine cartridges are manufactured to the highest possible standards in controlled clean rooms. Each cartridge is rigorously print tested in order that every user can be assured of the quality and performance they expect. Most Brother laser printers and all-in-ones have a separate drum unit and toner cartridge, which are replaced individually. This design helps reduce waste and is more economical than a single-piece design.