Replacement belt maintains your printer operation. Use only with the Brother HL-L9410CDN, HL-L9430CDN, HL-L9470CDN, HL-EX470W, MFC-L9610CDN, MFC-L9630CDN, MFC-L9670CDN and MFC-EX670W. Your printer will indicate when you need to replace it. Belt unit lasts for approximately 150,000 pages.