The Seiko 8420-6780 is a watch model based on the 8420 movement.
Parts List
| ES6W00GN00 | crystal |
| 25M22NA1 | crown |
| 0H1860N01 | case back gasket - case back gasket |
| 86570600 | crystal gasket |
| EA2160B41 | bezel gasket |
| DK26B | band - leather band |
| ZK38A | band - leather band |
| 08R16CGH | others - hour hand |
| 08R16CGM | others - minute hand |
| 0354815 | others - winding stem |
| 81502109 | others - screw |
| 82304903 | others - bezel |
| 82721200 | others - case ring |
| 84201380XG14 | others - dial |
| 84201380XN14 | others - dial |
| 84206780FZ | others - case |
| 89996430 | others - spacer |
| A140AS | others - push pin |
| DZ0041B01 | others - crown and stem gasket |
| ES6W00GN00 | crystal |
| 25M22NA1 | crown |
| 0H1860N01 | case back gasket - case back gasket |
| 86570600 | crystal gasket |
| EA2160B41 | bezel gasket |
| DK26B | band - leather band |
| ZK38A | band - leather band |
| 08R16CGH | others - hour hand |
| 08R16CGM | others - minute hand |
| 0354815 | others - winding stem |
| 81502109 | others - screw |
| 82304903 | others - bezel |
| 82721200 | others - case ring |
| 84201380XG14 | others - dial |
| 84201380XN14 | others - dial |
| 84206780FZ | others - case |
| 89996430 | others - spacer |
| A140AS | others - push pin |
| DZ0041B01 | others - crown and stem gasket |
Caliber 8420
