The Seiko 4N21-003S is a watch model based on the 4N21 movement.
Parts List
| 190WC9SN01 | crystal |
| 6M30B5SNA0 | crown - crown |
| 0F160BAA5 | case back gasket - case back gasket |
| DK10D | band - band |
| 3BA125F1BNG | others - second hand |
| 1BC050A1BAA | others - hour hand |
| A120BS | others - push pin (for lb) |
| 4N210040XS14 | others - dial |
| 4N2164 | others - machine code |
| DZ0040B01 | others - crown and stem gasket |
| 4N21003SRC | others - case |
| 82833515 | others - case ring |
| 4N21003S | others - case back |
| 08SC29NG | others - second hand |
| 07T23AFM | others - minute hand |
| 2BC075A1BAA | others - minute hand |