The Seiko 6640-8000 is a watch model based on the 6640 movement.
Parts List
| 305N04AN | crystal |
| 45M12NS | crown |
| 45M12NG | crown |
| FA2847B | case back gasket |
| DJ0060B | others - crown gasket |
Other models with the same movement
| 6640-6000 |
| 6640-6020 |
| 6640-7970 |
| 6640-8010 |