The Lexmark 51B2000 toner cartridge is a return program unit that offerd the user a cheap printing solution. Compatible with fine printers like the Lexmark MS317dn, this 51B2000 represents the very finest black and white prints on the market. Offering an estimated 2,500 prints, each of these genuine Lexmark 51B2000 toner cartridges are great value. Although the 51B2000 is one of the most reliable printing products on the market, Lexmark still offer a full guarantee on the cartridge directly.