The Seiko M421-500A is a watch model based on the M421 movement.
Parts List
| ES8W89LN00 | crystal |
| 0F230BAA1 | case back gasket - case back gasket |
| EG0115B01 | case back gasket - button gasket |
| 80608771 | pusher |
Other models with the same movement
| M421-5000 |
| M421-5010 |
| M421-5020 |
| M421-502A |
| M421-5030 |