The Seiko 8420-6400 is a watch model based on the 8420 movement.
Parts List
| RE2N40SN00 | crystal |
| 25M08NA4 | crown |
| 0G2435N01 | case back gasket |
| GB19A | band - metal band |
| DZ0040B01 | others - crown and stem gasket |
| 81180229 | others - bracelet fixing pipe |
| 81604259 | others - bracelet fixing pin |
| DZ0041B01 | others - crown and stem gasket |
Caliber 8420
