The following 3 products are guaranteed to work in your OKI B731 printer:
3 products
0.8p per page
FREE next-day delivery when you order before 5:15pm
1.4p per page
FREE next-day delivery when you order before 5:15pm
0.1p per page
FREE next-day delivery when you order before 5:15pm
The OKI B731 uses OKI 45439002 toner cartridges. OKI 45439002 toner comes in black; the black cartridge prints 36,000 pages.