The Seiko 8420-7840 is a watch model based on the 8420 movement.
Parts List
| K02N04SN00 | crystal |
| 26M04EE3 | crown |
| 0H1500N01 | case back gasket - case back gasket |
| 04V08DGM | others - hand |
| WI170 | others - other band |
| 04V08DGH | others - hour hand |
| 81501405 | others - case back screw |
| DZ0041B01 | others - crown and stem gasket |
Caliber 8420
