The Seiko 7439-503A is a watch model based on the 7439 movement.
Parts List
| ES6W03HM10 | crystal |
| 35M45NA1 | crown |
| 35M45NS1 | crown |
| 0G2450B01 | case back gasket - case back gasket |
| EB0055B01 | others - crown and stem gasket |
Caliber 7439
Seiko 7439-503A Watch Guide