Are you sure this is really compatible with the OKI C911 printer? I don't recognise the cartridge at all. Example of a cartridge that you sell and that I confirm is compatible with the printer:
https://www.digitec.ch/fr/s1/product/oki-45103713-y-toners-5682296?ip=5682296
The two items are two different products, both are compatible with the Oki C911dn: - OKI 45536413 (Y) : This is the toner cartridge. - OKI 45103713 (Y): This is the drum unit.