Original Lexmark C540X31G Black Developer Unit - LD Products
Amazon.com: Lexmark C540, C543, C544, C546, X543, X544, X546 Series High Yield Magenta Return Program Toner Cartridge (2,000 Yield), Part Number C540H1MG : Office Products
Lexmark Black & Color Imaging Kit for X543 & X544 Series MFPs & (C540X74G)