What is the difference between the toner cartridge and the drum unit? | Brother
brother Genuine DR251CL Drum Unit, Approx. 15000 Page Unit Life (DR-251CL) for Use with: MFC-9335CDW, HL-3150CDN, HL-3170CDW, MFC-9140CDN, MFC-9330CDW, MFC-9340CDW Black : Amazon.com.au: Computers