The Seiko 8420-5020 is a watch model based on the 8420 movement.
Parts List
| ES2N56SN00 | crystal |
| 25M02NS3 | crown |
| 0G1900N01 | case back gasket - case back gasket |
| 0Z0034B01 | case back gasket - crown and stem gasket |
| HB02A | band - metal band |
| HB02A-LKG | band - link |
| HB02A-BK1G | clasp - buckle |
| HB02A-PB1 | clasp - parts for buckle |
| HB02A-EP2 | others - endpiece |
| 81180229 | others - bracelet fixing pipe |
| 81604259 | others - bracelet fixing pin |
| DZ0041B01 | others - crown and stem gasket |
Caliber 8420
