The Seiko 4N21-5390 is a watch model based on the 4N21 movement.
Parts List
| SA2A55JN02 | crystal - crystal |
| 6M35D3SNW0 | crown - crown |
| 0F170BA1S | case back gasket - case back gasket |
| DC35AW | band - leather band |
| DC36AW | band - band |
| 3BA075F1BA6 | others - second hand |
| 1BD047ABBAL | others - hour hand |
| 1BK047AABAL | others - hour hand |
| 2BC067A1BAL | others - minute hand |
| 2BK067AABAL | others - minute hand |
| A100BS | others - push pin (for mb) |
| DZ0040B01 | others - crown and stem gasket |
| 0351155 | others - winding stem |
| 4N212350XS19 | others - dial |
| 4N212360XZ19 | others - dial |
| 4N2165 | others - machine code |
| 89942935 | others - back plate |
| 4N21539095A | others - case |
| 82836670 | others - case ring |
| 4N215390 | others - case back |