Premium Quality 64435XA Toner Cartridge compatible with the Lexmark T640, T640DN, T640DTN, T640N, T640TN, T642, T642DN, T642DTN, T642N, T642TN, T644, T644DN, T644DTN, T644N, T644TN. The use of compatible supplies does not void your printer warranty. Product Detail Ninestartechonline.com