Brother Genuine Drum Unit (yields approx. 30,000 pages based on 1 page per job and 50,000 pages based on 3 pages per job [letter/A4 simplex pages]. The number of pages may be affected due to a variety of factorsBrother Genuine Drum Unit, approximate 30,000 page yield (*approximately 30,000 pages based on 1 page per job and 50,000 pages based on 3 pages per job [letter/A4 simplex pages]. The number of pages may be affected due to a variety of factors including but not limited to media type and media size). All Brother Genuine supplies are designed as part of a complete intelligent printing system to provide superior quality. Brother Genuine toner is precisely balanced for even flow and consistent toner distribution. Use only Brother Genuine drums for results you can be proud of.including but not limited to media type and media size).