Lexmark
40X5924
is compatible in the following Printer Models:
Lexmark Mono Laser
Lexmark T640dn (4061-010)
Lexmark T640dtn (4061-010)
Lexmark T640n (4061-010)
Lexmark T640tn (4061-010)
Lexmark T640rn RFID (4061-0R0)