This is compatible drum unit for Brother OEM part #DR520, #DR620. The page yield of this Brother drum unit is 25,000 pages based on 5% page coverage. This drum unit is made of high quality standards and is guaranteed to meet or exceed OEM specifications. Toner Booth provides 100% guarantee all of its compatible cartridges and re-manufactured cartridges. You will also receive free shipping on all US order over $50.