Oki Okidata ML420 printer and Oki Okidata ML421 Printhead Printhead 
OKI offers the Replacement Printhead for the Microline dot matrix printers. This user-replaceable printhead has an average lifetime of 200 million characters in utility mode at normal 25% duty and 35% page density.
- Features: 9 pins
- Yield: Up to 400 million characters
- Compatibility: Oki Okidata Microline ML420 and Oki Okidata ML421. Genuine Oki Data – NOT clone.