Return Program Developer Kit is essential to Lexmark Print System performance. It is designed to work best with Unison toner that consistently delivers outstanding image quality, ensures long-life system reliability and promotes superior sustainability - all in an innovative, shake-free print system. It includes the cyan, magenta and yellow cartridges. Standout performance and maximum yield are a true investment in efficiency. Each cartridge yields approximately 300,000 pages in your Lexmark CX820dtfe, CX825dte, CX825dtfe, CX860dte, CX860dtfe, CX860de, CX825de, CX820de, CS820dte, CS820dtfe and CS820de. Genuine Lexmark supplies work best together with your Lexmark printer, delivering excellent print quality. Return Program Developer Unit is a patented device that is sold at a special price subject to the restriction that the developer unit may be used only once. Following the initial use, return the developer unit only to Lexmark for remanufacture and/or recycling.