These printers use the C734X20G cartridge:
Lexmark C 734
Lexmark C 734 DN
Lexmark C 734 DTN
Lexmark C 734 DW
Lexmark C 734 N
Lexmark C 736
Lexmark C 736 DN
Lexmark C 736 DTN
Lexmark C 736 N
Lexmark X 734
Lexmark X 734 DE Color MFP
Lexmark X 734 DE
Lexmark X 736
Lexmark X 736 DE Color MFP
Lexmark X 736 DE
Lexmark X 738
Lexmark X 738 DE Color MFP
Lexmark X 738 DE
Lexmark X 738 DTE
Lexmark XS 736 DE