Genuine OEM Lexmark MS312 DNw Toners
The Lexmark MS312 DNw uses 50F1H00 or 50F1H0E black toner, while 40X8023 is the separate fuser. A toner notice and a fuser notice refer to different parts, even though both appear for this printer.
Toner Buzz carries genuine Lexmark black toner under both 501H order codes, along with the 40X8023 fuser. Choose toner for a low-toner message; select the fuser only when the printer identifies that maintenance component.