The Seiko 4N21-5010 is a watch model based on the 4N21 movement.
Parts List
| RE3W09JN01 | crystal - crystal |
| 32M09NA1 | crown - crown |
| 32M09NS1 | crown |
| 0F170BAA3 | case back gasket - case back gasket |
| DL15B | band - band |
| DL14B | band - leather band |
| 3BA075F1BNG | others - second hand |
| 3BA075F1BNS | others - second hand |
| 05T05A1M | others - minute hand |
| 1BA037A1BAF | others - hour hand |
| 2BA057A1BAF | others - minute hand |
| A120BS | others - push pin (for lb) |
| 4N210130XS14 | others - dial |
| 4N210130XS23 | others - dial |
| 4N215010 | others - case back |
| 4N21501075 | others - case |
| 4N2150107E | others - case |
| 4N2164 | others - machine code |
| 82833190 | others - case ring |
| EB0055B01 | others - crown and stem gasket |
| 0351155 | others - winding stem |
| 07SC04NG | others - second hand |
| 07SC04NS | others - second hand |
| 05T05A2M | others - minute hand |
| 1BA037A1BAH | others - hour hand |
| 2BA057A1BAH | others - minute hand |