For crisp text output and unbeatable reliability from your OKI C301 or C321 laser printer, install a genuine OKI Black High Yield Toner Cartridge (44973536). Order a replacement black toner cartridge when you see a 'K Toner Low' error message. Then swap it for the empty cartridge when 'Toner Empty' is displayed and continue printing straight away. This standard yield toner cartridge is packed with enough black toner to print 2,200 pages.