OKI PRO 9431 | OKI PRO 9541. To fit OKI PRO 9431 | PRO 9431EC | PRO 9431EV. Cyan Toner for OKI PRO 9431. Magenta Toner for OKI PRO 9431. Black Toner for OKI PRO 9431. Toner Full Set for OKI PRO 9431. OKI PRO 9541 | PRO 9541EC | PRO9541EV Laser Printers.