All genuine Brother printer supplies are designed as part of an entire printing system and are designed with Brother products in mind, to provide a superior degree of quality. Genuine Brother toner is delicately balanced to provide even flow and toner distribution. Toner cartridges are designed for use in Brother HL-3140CW, HL-3170CDW, HL-3180CDW, MFC-9130CW, MFC-9330CDW and MFC-9340CDW. Each cartridge yields approximately 2,500 A4 or letter-size, single-sided pages. Your printer will indicate when you need to replace it.