The Seiko 5421-0020 is a watch model based on the 5421 movement.
Parts List
| 190N69AN00 | crystal |
| 35M94NA1 | crown |
| 35M94NS1 | crown |
| 35M96NA3 | crown |
| 0G0055B01 | case back gasket - crown and stem gasket |
| 0A1700N0 | case back gasket |
Caliber 5421
Seiko 5421-0020 Watch Guide