The Seiko 8420-6440 is a watch model based on the 8420 movement.
Parts List
| ES8N92SN00 | crystal |
| 25MHM02NE3 | crown |
| DG1590B4A | case back gasket |
| 0Z0034B01 | case back gasket - crown and stem gasket |
| HI072 | others - other band |
| DZ0041B01 | others - crown and stem gasket |
Caliber 8420
