The Seiko 4N21-0180 is a watch model based on the 4N21 movement.
Parts List
| 200A02SN02 | crystal - crystal (sapphire) |
| 30M81DA4 | crown - crown |
| 30M81NS4 | crown - crown |
| AC004BA11 | case back gasket - crown and stem gasket |
| 0F170BAA3 | case back gasket - case back gasket |
| MK55E | band - band |
| DA48BW | band - band |
| DA59BW | band - band |
| MK38F | band - band |
| 08SC31VG | others - second hand |
| 08T25JGH | others - hour hand |
| 08T25JGM | others - minute hand |
| 08T25JSH | others - hour hand |
| 08T25JSM | others - minute hand |
| 08T73JGH | others - hour hand |
| 08T73JGM | others - minute hand |
| A130AS | others - push pin (for lb) |
| 4N210380XG14 | others - dial |
| 4N210390XS14 | others - dial |
| 4N210820XS19 | others - dial |
| 4N211020XG14 | others - dial |
| 4N211720XG14 | others - dial |
| 4N2164 | others - machine code |
| 4N2101807EA | others - case |
| 4N21018075D | others - case |
| 4N21018075E | others - case |
| 4N21018075A | others - case |
| 4N210180 | others - case back |
| 4N21018075B | others - case |
| 4N21018075C | others - case |
| 82832715 | others - case ring |
| 08SC653G | others - second hand |
| 08SC653S | others - second hand |
| 0351156 | others - winding stem |
| 08SC29NG | others - second hand |