The Seiko 4N21-0590 is a watch model based on the 4N21 movement.
Parts List
| 170A17SN02 | crystal |
| 6M30B5NNG2 | crown - crown |
| 0F150BAA5 | case back gasket - case back gasket |
| 0H1600B01 | case back gasket - case back gasket |
| TB19A | band - metal band |
| 3BA075F1BNG | others - second hand |
| DZ0040B01 | others - crown and stem gasket |
| 0351155 | others - winding stem |
| 81606439 | others - bracelet fixing pin |
| 81181459 | others - bracelet fixing pipe |
| 81607559 | others - bracelet fixing pin |
| 82841070 | others - case ring |
| 4N210590 | others - case back |
| 4N21059075 | others - case |
| 4N211150XS14 | others - dial |
| 4N2164 | others - machine code |
| 82280435 | others - bezel |
| 07T31DGH | others - hour hand |
| 07T31DGM | others - minute hand |
| 1BD050LDBDG | others - hour hand |
| 2BD072LABDG | others - minute hand |