The Seiko 8420-6390 is a watch model based on the 8420 movement.
Parts List
| SA9N50SN00 | crystal - crystal |
| 25M02NA3 | crown |
| 0G1900N01 | case back gasket - case back gasket |
| MK08B | band - band |
| 07R03NGM | others - minute hand |
| 842063904F | others - case |
| 82712660 | others - case ring |
| 84200960XG14 | others - dial |
| A120AS | others - push pin |
| 0354815 | others - winding stem |
| 07R03DGM | others - minute hand |
| DZ0041B01 | others - crown and stem gasket |
Caliber 8420
