Brother printers are renowned for quality and results - especially when using genuine Brother supplies. The genuine Brother DR-3325 drum unit is an integral part of your laser printer, and needs to be replaced around about every two to three TN-3360 toners, three to four TN-3340 toners, or nine to ten TN-3310 toners, you have depleted. Your printer will warn you when the drum will soon need to be renewed. The drum unit does not contain any toner - it's function is to transfer the image onto the page. With Brother laser products the toner and drum work independently – this is cheaper to run than those where the two units are combined. If one runs out, you don't have to replace both items simultaneously, substantially reducing waste, saving precious resources and your cash. Ensure crisp clear prints every time using Original Brother consumables.