These printers use the 42377801 cartridge:
Click On a Printer to View it's Cartridges
Okidata Dot Matrix 420
Okidata Dot Matrix 421
Okidata Dot Matrix 490
Okidata Dot Matrix 720
Okidata Dot Matrix 790
Okidata Dot Matrix 791
Okidata Microline 300
Okidata Microline 400
Okidata Microline 420
Okidata Microline 420 N
Okidata Microline 421
Okidata Microline 421 N
Okidata Microline 490
Okidata Microline 490 N
Okidata Microline 491
Okidata Microline 491 N
Okidata Microline 720
Okidata Microline 721
Okidata Microline 790
Okidata Microline 791
Okidata ML 420
Okidata ML 420 TURBO
Okidata ML 421
Okidata ML 490
Okidata ML 491