The Seiko 4N20-0420 is a watch model based on the 4N20 movement.
Parts List
| 165W13HK01 | crystal |
| 30M57NA1 | crown - crown |
| 30M57NS1 | crown - crown |
| 0F140BAA3 | case back gasket - case back gasket |
| AC004BA11 | case back gasket - crown and stem gasket |
| HZ68A | band - metal band |
| HZ69A | band - metal band |
| 06Y03DGM | others - minute hand |
| 81606439 | others - bracelet fixing pin |
| 81181459 | others - bracelet fixing pipe |
| 82840910 | others - case ring |
| 4N200420 | others - case back |
| 4N20042075 | others - case |
| 4N2004207E | others - case |
| 4N200700XG14 | others - dial |
| 4N200720XS13 | others - dial |
| 4N2061 | others - machine code |
| 0351155 | others - winding stem |
| 06Y03DSM | others - minute hand |
| 06Y03NGH | others - hour hand |
| 06Y03NSH | others - hour hand |