The Seiko 2639-5020 is a watch model based on the 2639 movement.
Parts List
| SA6N99KN00 | crystal |
| 35R05NS1 | crown |
| 013060B01 | case back gasket |
Caliber 2639
Other models with the same movement
| 2639-5000 |
| 2639-5010 |
| 2639-5030 |
| 2639-5039 |
| 2639-7000 |
| 2639-7009 |
| 2639-8000 |
| 2639-8009 |