Genuine OEM Brother HL-5280DW Toners
The HL-5280DW uses two black toner cartridges and a separate drum. TN-550 is standard-yield. TN-580 is high-yield. DR520 is the drum, not a third toner capacity.
The genuine Brother lineup at Toner Buzz covers TN-550, TN-580, and DR520 for this printer. Pick either toner cartridge according to how much you print, and choose DR520 only when the drum itself needs changing.