Installing a genuine OKI Black Toner Cartridge (44917602) means consistent high quality output and reliability from your OKI laser printer. Order a new toner cartridge when you see Toner Low displayed on your printer, as the current cartridge will only print around 100 more pages. Install it when you see the Toner Empty message so you can resume printing as quickly as possible. This standard yield toner cartridge is packed with enough black toner to print 12,000 pages and is designed for B431, B491 and MB491 printers.