The Seiko 3421-5120 is a watch model based on the 3421 movement.
Parts List
| SA3N98GN00 | crystal |
| 30M06NA1 | crown - crown |
| 30M06NS1 | crown - crown |
| 0G0055B01 | case back gasket - crown and stem gasket |
| 0A1900N01 | case back gasket - case back gasket |
| 0A1900N0 | case back gasket |
| DL36A | band - band |
| DL34A | band - band |
| DL35A | band - band |
| 08T04NGH | others - hour hand |
| 07T08NGM | others - minute hand |
| 08SC14NG | others - second hand |
| A120BS | others - push pin (for lb) |
| 34210790XB14 | others - dial |
| 34210790XG14 | others - dial |
| 34210800XS17 | others - dial |
| 34211 | others - machine code |
| 3421512011 | others - case |
| 83118250 | others - case ring |
| 3421512025 | others - case |
| 0354546 | others - winding stem |
| 08SC14NS | others - second hand |
| 07T08ASM | others - minute hand |
| 08T04ASH | others - hour hand |
Caliber 3421
